10. Heavenly Roast Lamb

A break in the rain clouds offered me the rare opportunity to fire up the oven last weekend so I decided to take full advantage of the interlude to cook-up a roast to die for.

The clay oven is fabulous at high temperature for cooking the perfect pizza but if you allow these babies to cool down somewhat, you can use the residual heat to cook sublime roast joints of meat.  It is the way that the ovens cool that creates the ideal temperature profile for cooking perfect roasts.  Last weekend I decided to try roasting a whole leg of lamb and, of course, I recorded the whole thing so I could share it on the blog.

The spices make it look yellow!

The spices make this leg of lamb yellow!

Stage One: Prepare your joint of meat
Normally, with a joint of free range, organic meat I would suggest doing very little with it.  With lamb, maybe some garlic, fresh rosemary, a splosh of olive oil and some salt and pepper.  This time though my wife marinated the lamb over night in a mix of Moroccan spices (a Nigella Lawson recipe I think).  I recommend trying this if you fancy something a little different – it is truly delicious.  Whatever you decide to do make sure your lamb is prepared and ready to go.  Place the joint of lamb in a roasting tin and keep covered at room temperature until you are ready to cook it.

The oven reaches 350 degrees C

The oven reaches 350 degrees C

Stage Two: Fire her up!
Firing the oven for a roast is no different to firing it up for cooking pizzas.  Follow the technique I outlined in this earlier post.  Keep the “full blaze” fire going for a good hour or so because you want residual heat in the whole oven structure – in the bricks and the walls of the oven itself.  You can see from the photo that on this occasion my oven reached 350 °C (it took around 2 hours 15 minutes to reach this temperature).  You may think that this is relatively cool and you would be right!  This was the first time the oven had been fired since last year and so it had a whole winter’s worth of moisture absorbed within it which had the effect of lowering the maximum temperature.  Not to worry though! If you were to put a joint of meat in the oven at this temperature it would be cremated in minutes!

Stage Three: Wait for it!
Allow the fire to burn down.  You can help this along by spreading the embers across the oven floor.  At this stage you need to keep your eye on your temperature gauge which will slowly begin to drop.  When the temperature reaches 260 °C put the tray, together with the joint of meat, into the oven.  Leave the door and chimney open for now.  Cooking the meat at this high temperature for the first part of the roast is what Hugh Fearnly-Whittingstall calls the half-hour sizzle and is a crucial part of the roasting process.  Over the next 15-20 minutes or so the temperature will slowly drop.  When the oven temperature drops to approximately 190 °C, block the door and the chimney.  Leave it like this until the meat is cooked.

Cooked to perfection

Cooked to perfection

How long does it take?
Well this obviously depends on the size of the joint of meat and the type of meat you are cooking.  I cooked this leg of lamb for 1hr and 40 minutes after the door and chimney was blocked.  When I took the joint out, the oven temperature was still at 170 °C.  It would have stayed hot for many hours longer so, if your meat needs a little more cooking time, whack it back in!

That’s it.  Simple eh?  Any meat cooked in the oven in this way is mouthwateringly moist, extremely tasty and just falls off the bone.  You should also try chickens (complete with roast spuds) and my favourite, belly pork which is truly sublime! Try it for yourself and let me know how you get on.

Happy roasting!

15 thoughts on “10. Heavenly Roast Lamb

  1. Hello! I have a clay oven to 100 years, still works perfectly. it is longer than the fins and is without a chimney. We bake a whole lamb. Old people know that the oven is ready, when the inner walls are white set. The door is moving, and after the lamb in it and embers scattered, sealed with a paste of flour and water.

  2. Helen – you are right about the clay…and btw – I wouldn’t mind your contact dets if you are Anglia based – I sourced mine from Chris at Hesketh Potters – really helpful people too. In the end I chose craft crank for its elasticity and although per kilo is more £ than std red, I was benchmarking cost against buying the Spanish style BBQ / ovens…and am very much on the credit side.

    Simon- the book is great and has been a fantastic help…it’s a good, fun read as well!
    I scouted the reclaim yards for a timber base and was given some jaw-dropping figures so decided to go via breeze blocks (airated type) from Wickes which reduced the cost to a third.
    Lessons learned after 1 weeks usage?
    1) Don’t hurry it – we live in the UK and until this week the weather has been damp if not worse – really let it dry out well before you take the former out, and then fire it a couple of times (you might as well enjoy the experience and cook in it at the same time 😉
    The 4+ hours before you cut the door out turned out to be 4 days for me.
    2) Keep it spherical or even dome shaped – if you create too much of a slope then clay chooses the least course of resistance when obeying gravity, despite the former.
    3) For the insulation layer – try straw instead of wood-chips….its heavy to work with but once ready builds very quickly in larger slabs.
    4) Clay and sand as mortar is ‘ok’ but if I came this way again (and I surely will), then for the join to the brick arch, the arch itself and around the oven base perimeter I’d be tempted to include cement as well….and I may be showing some ignorance here.
    5) Julie smoothed the last layer off with a wet paintbrush – the finish is amazingly silky and very appealing.
    6) Play with it / experiment on cooking times – these ovens sure are efficient. Sausages take 15 seconds 😉
    Pizzas are, as promised, sublime…but tricky. My son found the answer – if you have enough of a flour dusting on the base to make sure it slides onto a plate, then it will transfer easily to the baker’s peel / pizza paddle…but if you are bread makers you probably already knew this.

    The next part is an experiment – I plan to spray the dome with Thermacure high temperature stove paint – Almond colour for aesthetics…will let you know how that goes…

    Best wishes,
    Dave S (dsav@talktalk.net)

  3. Hi Will
    Your website inspired me here in Australia, we made our oven over the course of two weekends. Our friends and family love making the pizzas and yes we do lamb most Sundays!
    We rub olive oil, mustard, garlice rosemary and honey at the end ! it turns out so delicious evey time.

  4. Thank you for the excellent information it’s really inspired me and I plan to begin building an oven as soon as possible.

    I do have a couple of questions though.

    Do you have a door on your oven or do you just block it with something? I like the idea of having a door and would like to know what to make it from.

    Also, has anyone taken temperature readings over a period to chart the temperature drop?



    • Hi will. Thanks for the kind comments. I’m not sure why you would want a door in the back of your oven. The front door is adequate. Secondly I have nit recorded the temperature profile of the oven but will do next time I fire it (tomorrow!).

      All the best


    • Will – we did make a ‘door’ – stencilling out the irregular shape onto thick plywood, adding a drawer handle, and lining it with cooking foil at time of use having soaked the door in water first.
      It works very well when you want to clamp the over down and let it cook.
      Temperature readings show that it reached 550 degrees during firing, we let it cool then clamped down seemed to maintain 300-ish for a LONG time (it was still going strong sub 200 degrees 4 hours later…but by we were eating by then so had lost track a little.

    • I do think the same technique would work for a tandoor. I build a brick tandoor next to my brick oven in my backyard a couple years ago and I LOVE it. There are a couple things different about what you are going for in a tandoor, though, so you could even cut back some. If you are considering a tandoor, post something and I would be hapy to post some of the things I learned from when I built mine. Since I built my tandoor, I don’t think I have ever used my outdoor grill again….I always just use the tandoor. YUM!

  5. Simon,
    I have finished my oven, the final layer went on yesterday.
    I used your mesurements and I used 13 bags of 12.5 of terracotta clay.
    The whole family and a load of friends are over on Saturday for pizzas for lunch then lamb rolls in the evening. Can’t wait!
    I have taken photos all the way through, how can I get them to u?
    One last thing to anyone making an oven, take your wedding ring off!!! I didn’t and I think it’s in the insulation layer.

    • Wonderful Nic – congratulations! I’d give the oven a test firing sometime this week so you can get to know how long it takes to reach temperature etc. I cooked a fabulous roast chicken in mine on Sunday which I’ll blog about shortly.

      As for photos, if you upload them to a site like Flickr or any free photo hosting website, you can send me the link on here.

      Best of luck


  6. Hi Simon.
    I can’t wait to try lamb in my clay oven with no clay.lol.
    Couple of questions if you don’t mind, when I have made my oven and all ready to cook, can I use a clay door for the door and some some of hat made from clay for the chimney or do you recommend a wood that won’t catch alight.
    Last thing, eBay are selling crank clay, it’s gray, it says it’s ideal for pizza ovens. It also says it’s got heavy grog 20/30. Not sure what this means, will it be ok to use and if so will it still need sand. If not I’ll keep on searching.
    Thanks for your help.

    • Hi Nic not sure if a door and chimney stop made from the same clay mixture as the oven will work – it is quite friable when it is dry and so I think they would end up cracking. I’d make a door out of wood and as for a chimney stop, mine is made from scrunched up newspaper, wrapped in masking tape then covered in aluminium foil. It works a treat!

      Finally, I know nothing about potters clay but if you read the FAQ you will see others have been investigating it:


      Good look.


    • Hi Nic,
      I think Sues article about clay explains the best clay to use. Earthenware is just great for the job, crank would be great too but its expensive in comparison. Crank clay contains plenty of grog (ground up bits of fired clay) which gives it great pot making and sculpting qualities. You will find it much cheaper to buy some lovely red earthenware clay (otherwise known as terracotta) the same clay as plant pots are made from. Incidently red earthenware is the cheapest clay you can buy-bonus!
      As for the door, clay would be very unsuitable unless it was fired properly in a kiln, an oak door will not burn (too much) if you soak it well in a water butt prior to using it in the oven,
      Hope that helps, Helen (Anglia clay Supplies)

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