Don’t bother putting in any kind of creamed tinned soup or stew. It’ll only curdle unless your slow cooker is really really slow. Add the real mushrooms for the last hour of cooking along with extra veg. Except for peas - add for the last 5 mins if using frozen peas. For me, I’d use a couple of tins of crushed/diced tomato for liquid, topping up with water or stock or red wine. Trim the worst of the fat off the beef, then brown it before putting in the slowcooker. Brown any onions if using too. If you like a really really thick gravy, add 1 tablespoon of cornflour blended with 1/2 cup COLD water for the last 15 mins of cooking and stir it in well - this will thicken things up but will blunt the flavour, so feel free to use as much extra flavoring as you want if you plan to do this. Blend the cornflour with the water really well so it doesn’t go lumpy.
Don’t bother putting in any kind of creamed tinned soup or stew. It’ll only curdle unless your slow cooker is really really slow. Add the real mushrooms for the last hour of cooking along with extra veg. Except for peas - add for the last 5 mins if using frozen peas. For me, I’d use a couple of tins of crushed/diced tomato for liquid, topping up with water or stock or red wine. Trim the worst of the fat off the beef, then brown it before putting in the slowcooker. Brown any onions if using too. If you like a really really thick gravy, add 1 tablespoon of cornflour blended with 1/2 cup COLD water for the last 15 mins of cooking and stir it in well - this will thicken things up but will blunt the flavour, so feel free to use as much extra flavoring as you want if you plan to do this. Blend the cornflour with the water really well so it doesn’t go lumpy.