Mix the cheese, chopped bacon, and sour cream.
If sour cream is thick, then add milk, and if not, then you will not need milk.
Sprinkle with salt and pepper to taste.
Add the onion and mix well.
Spread the mass on the bread.
Preheat the oven and bake for 15-20 minutes at 200 deg.
Look at the degree of brown colour.