I got the recipe from

https://www.thecountrycook.net/crock-pot-mississippi-pot-roast/

1 3 lb chuck roast
2 tablespoon olive oil or vegetable oil
salt & pepper to taste
1 packet ranch dressing mix
1 packet dry onion soup mix
½ cup salted butter 1 stick
8 peperoncini peppers

My addition (optional)
1 tbsp Worcestershire sauce
2 tbsp red wine