Preheat your grill and a cast iron skillet to medium heat.
Slice your dove breasts thinly. I used a mandolin to get 1/8 to 1/4 inch slices, but you can use a knife. If you use a mandolin, I find it best to leave the dove slightly frozen.
Thinly slice your green bell peppers and onions.
Melt 2T of butter on your skillet and pour your vegetables in. Cook for 20 minutes stirring occasionally.
Add your Worcestershire sauce and stir.
Add your sliced dove breasts to the skillet and stir.
Add garlic pepper and stir well.
Cook dove and veggies for an additional ~7 minutes stirring occasionally. The breasts should still be slightly pink on the inside.
Cover the meat and veggies with slices of white American cheese.
Close your grill for 1-2 minutes, or until the cheese becomes melty.
Using ~3T of butter, butter your bread and toast them for around a minute or until desired crispiness.
Place meat mixture on bread. Enjoy!