Cover, reduce heat to low, and simmer 10-15 minutes.
Preheat oven to 375F.
Stir the peas into the beef mixture. Pour the beef mixture into a small baking dish (approximately 8x8 inches).
3/4 cup frozen peas
Spread the potatoes across the top of the meat in the dish, edge to edge, completely sealing the meat in to trap the moisture and juices.
Bake until the top is starting to brown, approximately 20 minutes. Serve warm.
If you are trying to prevent sauce from pooling on top, make an ever so subtle mound in the center of the dish with the potatoes and have the potatoes very slightly slope downward toward the edges and corners. This should help encourage the sauce to go back in the bottom instead of sitting on top.