Here is the recipe I use for Sausage Casserole.
1 tbspn olive oil
1kg of sausages.
500 grms mixed frozen vegetables.
1 425 tin diced tomatoes.
2 cups gravy.
dash of wistershire sauce.
fry onions in oil. When they are going opaque, add sausages. Cook until sausages are done then transfer to crock pot. Add tomatoes, gravy and Worcestershire sauce. Cook on high for 3 hours. Add in vegetables and cook for another hour.
If I am organised enough when I do the shopping for the oamc, I cook the sausages and onions ahead and freeze them. Then when we have the meal, everything is ready to go in the slow cooker.
I also have done this recipe with baked beans but now I get too many complaints when they see them. I think it really adds to the flavour but my children think baked beans are the most gross thing on this earth.