01 -
Heat oven to 400°F (204°C).
02 -
In a skillet, brown the ground beef over medium heat until fully cooked, then drain excess fat.
03 -
Add chopped onion and garlic powder to the skillet with the beef; sauté until the onion is translucent and tender.
04 -
Transfer the beef and onion mixture into an ungreased 9x13-inch casserole dish, spreading evenly.
05 -
Evenly layer the uncooked white rice over the beef mixture, then spread chopped mushrooms on top of the rice.
06 -
Pour the French onion soup and beef consommé evenly over the layered ingredients.
07 -
Arrange sliced butter evenly across the surface without stirring.
08 -
Cover casserole tightly with aluminum foil and bake for 50 minutes.
09 -
Remove casserole from oven, stir well; if rice is tender, serve warm. If rice remains firm, recover with foil and bake an additional 10 to 15 minutes before serving.