Preheat oven to 375 degrees F. Spray an 8 x 8 baking pan with non-stick spray or coat with EVOO. Set aside
In a large fry pan, add oil and onion; cook over medium heat until translucent.
Add ground beef and cook until browned.
Remove from heat and drain excess fat
Stir in salt, pepper, taco seasoning and water
Simmer, about 10 minutes, until thickened.