For the batter mix, whisk together all the batter ingredients until a smooth mixture is formed. Set aside for one hour.
Preheat the oven 250C/500F/Gas 9.
For the mixed grill, heat a frying pan until hot, then add one tablespoon of olive oil and sear the lamb cutlets, sausages and tomato halves, then set aside.
Add the mushrooms and cook through.
Heat a separate pan until hot, then add the remaining oil and cook the onion and bacon until golden.
Pour the batter into the pan with the onions and bacon, then place the meat and vegetables on top of the batter. Place in the oven for 15-20 minutes until risen and golden.
For the onion gravy, heat a pan until hot, then add the oil, onion and thyme and cook until soft, for about 15-20 minutes.
Add the wine and cook until reduced by half. Then add the stock and simmer for 10-15 minutes.
Serve the mixed grill toad-in-the-hole with the onion gravy on the side.