Are roasting times affected when there is a bone in it?

[SilentBoob]

I am all of a muddle.

I have a 4.090kg shoulder of lamb with a bone in the middle of it.

Have used Wiki meat roast calculator and it says...

17:05 Preheat oven for 25 minutes to 220 °C ( 425 °F - Gas 7 - Hot )
17:30 Check oven has reached temperature, place the meat in a roasting tin, cover with foil and place in the oven
17:30 Roast for 30 minutes at 220 °C ( 425 °F - Gas 7 - Hot )
18:00 Reduce the oven temperature to 160 °C ( 325 °F - Gas 3 - Moderately slow/Warm )
18:00 Roast for 2 hours and 10 minutes
20:10 Take the meat out of the oven.
20:10 Cover loosely with tin-foil and leave to rest in a warm place for 20 minutes.
20:30 Carve the joint and serve.

Does that account for the fact that it is a whole round shoulder with a bone in the middle?

Yes it takes longer if bone in. I can't tell you how much longer but there should be sites if you google it, just remember to select bone-in times. You can get boned rolled shoulder so I would check another site if it doesn't say.

That's fine. It's the total weight of the piece that dictates the time. Doesn't really matter if it's boneless, boneless and stuffed, or bone-in as long as you weigh it in the state it'll be when it goes into the oven. You're giving it what looks like 45 mins per kg... 3 hours-ish total. If anything, the bone acts as a heat conductor which brings the time down a little.

Thank you both.

In the oven for another 1/2 an hour then rest / keep warm.

Sadly the dog crapped on the carpet and I lit some incense to try and cover the smell and now my whole house smells like a particularly unpleasant public lavatory. Lovely. Everything else seems to be going okay though.

Can't decide what to wear.

Spray febreze/anything smelly on the carpet, put some garlic slivers in the lamb and sprinkle rosemary on top and it's all smell great...oh, and have a glass of wine - throwing a good slug over afore-mentioned lamb

Carpet removed to the roof.

Basil and garlic starter about to go into oven.

Can't have wine. Pregnant.

Shame...hope it all goes well (tummy growling)