- Set oven to broil and move rack to top level.
- Arrange slices of bread on the baking sheet and lightly toast each side under the broiler until golden brown. Watch carefully!
- Meanwhile, combine grated cheese, mustard, Worcestershire Sauce, beer, salt, egg yolks, milk and flour in mixing bowl. Mix together with a fork until well blended. You can add a bit more milk, if necessary, to moisten the mixture so it can spread easily.
- Remove bread from broiler and move the rack down to the middle level.
- Spread each slice thickly (about 3–4 Tbsp) with the cheese mixture. Make sure you spread the mixture to the edges of the bread.
- Sprinkle with green onions, diced sweet peppers and freshly ground black pepper.
- Return to oven and broil for 3–5 minutes until cheese is bubbling and golden.
Serve with sliced tomatoes and hot sauce if desired.