Prepare Vegetable Filling (if using): Dice 1 cup of vegetables into small pieces. Heat 1 teaspoon olive oil in pan over medium-high heat. Add minced garlic and vegetables. Sauté for 3-5 minutes until soft. Set aside to cool.

Prepare Bacon Filling (if using): Dice 2 slices bacon into small pieces. Cook over medium heat with minced onion and garlic for 5-8 minutes until bacon is crispy and onion is soft. Drain excess fat and set aside.

Prepare the Eggs: Crack 3 large eggs into a clean bowl. Beat vigorously until completely uniform with no white streaks visible. Whisk in salt and pepper thoroughly until mixture is smooth and consistent.

Heat the Pan: Heat 1/2 tablespoon butter in 8-inch nonstick pan over medium-low heat. Make sure butter coats the entire bottom of the pan.

Cook the Omelette: Pour in beaten eggs and swirl pan to distribute evenly. Cover pan and cook without stirring for 2-3 minutes.

Set the Edges: As edges begin to set, gently push them inward with spatula. Tilt pan so uncooked egg flows underneath. Continue this process until eggs are mostly set, about 5-6 minutes total.

Flip and Fill: Carefully flip omelet and turn off heat. Sprinkle cheese over entire surface. Add prepared fillings to one half only.

Fold and Serve: Using spatula, fold empty half over fillings. Slide onto plate and serve immediately while hot.