Bring 1 3/4 cup of salted water to a boil. Add in Basmati rice and return water to a boil. Reduce heat to low and cook for 15 minutes or until liquid is absorbed.
While is cooking preheat oven to 350 degrees F. Spray medium size skillet with cooking oil and heat over medium high heat. Add in onions and cook 2-3 minutes. Add in mushrooms and cook an additional 3 minutes.
Add in mini meatloaves, beef stock, salt and onion powder. Add rice and mix well.
Slice peppers in half and remove seeds. Stuff each pepper with rice mixture and place in a shallow baking sheet. Bake for 15 minutes.