Sausage & Lentil Stew

This came about because I had some puy lentils that I bought for something else and then never used.  I decided to make something along the lines of a cassoulet but with lentils instead of haricots.  Then, because we eat as a family and my son is a little conservative, I decided to use ordinary bangers rather than pieces of pork and continental sausage.  Borrowing a few ideas from another recipe produced the following result, which is rather tasty.  It serves 5-6.

Ingredients:
450g British pork sausages, cut into chunks.
250g puy lentils
250-300g passata (tinned chopped tomatoes would probably be just as good)
1 small onion
1 carrot, chopped.
1 or 2 cloves garlic
1 vegetable stock cube

Process:
Wash the lentils.  Then add the stock cube to a pan of boiling water, add the lentils and carrots and simmer for 20 minutes.  Drain, saving the stock.
Meanwhile, fry the onions, garlic and sausages in a little oil until browned.  Then add the passata and heat through.
Combine the sausage mixture and drained lentils in a casserole dish.  Add enough stock to make the mixture moist but not liquid.
Cook in  a low oven (gas mark 1) for at least an hour.  Stir once or twice.
Serve.  I accompanied it with spuds and broccoli.

This dish has a strong rich flavour and doesn't really need much in the way of herbs or spices.  I guess you could add some chives or black pepper, or possibly some rosemary or allspice.  If you're so inclined, you could experiment with different types of sausage instead of plain pork ones.

Baking question

Cake recipes which use whipped egg whites to make the cake rise always seem to use plain flour.  Does anyone know whether these recipes would also work with self-raising flour?  Or would the raising agent in the flour somehow negate the effect of the eggs?  I know the egg whites are supposed to be sufficient on their own, but sometimes I feel a little backup wouldn't do any harm.