Preheat the oven to 375°F with a rack in the middle position (double-check that the rack sits level so your eggs bake evenly). Line a rimmed quarter sheet pan or metal 9x13-inch baking pan with parchment paper, then mist the parchment with nonstick oil spray. The parchment is your no-stick insurance policy—it lets you lift the whole omelet right out of the pan for clean, easy cutting.

In a large mixing bowl, whisk the eggs, egg whites, and milk until the mixture is well blended and a little frothy, with no streaks of white remaining. Whisk in the salt, pepper, and optional herbs.

Pour the egg mixture into the prepared pan. Now the fun part: decorate the top with your pre-bake toppings. You can go with one flavor across the whole pan, or divide it into two or three sections and vary it up, like I do. Just remember the golden rule—any veggies or meats going on before baking should be fully cooked and patted dry (see notes), and delicate toppings like lox, fresh tomato, and raw onion wait until after baking.

Bake for 20 to 25 minutes, until the eggs are just set in the center with no jiggle when you gently shake the pan (start checking at the 18-minute mark—ovens vary, and pulling the eggs at “just set” is the difference between silky and rubbery; they’ll finish firming up with carryover heat).

Let rest in the pan for 3 to 5 minutes, then use the parchment to lift the whole omelet onto a cutting board. Cut into 6 squares, add any after-baking toppings, and serve warm.