1/3 cup all-purpose flour or 1/4 cup (35 grams) cornstarch (gluten-free option)
8 large eggs
1 1/2 teaspoons kosher salt
Freshly ground black pepper to taste
1 package (10-ounce or 283-gram) frozen chopped spinach thawed and squeezed of excess liquid
3 scallions minced (white and green parts)
1 cup (4 ounces or 115 grams) white cheddar coarsely grated
Arugula or another salad green, halved cherry tomatoes, and minced chives optional
Equipment
oven
10×15-inch rimmed baking sheet (jellyroll size)
parchment
large bowl
whisk
cooling rack
clean kitchen towel
spatula
Directions
Heat oven to 350°F. Line the bottom and sides of a 10×15-inch rimmed baking sheet (jellyroll size) with a larger piece of parchment, pressing it into the inner sides and corners.
In a large bowl, whisk together milk and flour until smooth. Add eggs, salt, and many grinds of black pepper and whisk until the eggs are evenly mixed. Stir in spinach, breaking up any clumps, then scallions. Pour into prepared pan.
Bake the omelet, rotating it once just so that it bakes in an even layer, until the edges and most of the center are set (a little runny is fine), about 10 to 12 minutes. Sprinkle the top with cheese and return to the oven for another 2 to 3 minutes.
Remove from the oven and slide the omelet and its parchment onto a large cooling rack. Grab a clean kitchen towel to protect your hands from the heat as you roll. Begin rolling the omelet from a shorter end, lifting the parchment to help roll the omelet tightly. As you lift the parchment over the roll with one hand, use the edge of a spatula to keep tucking the log under as you roll. Roll the omelet onto a serving plate.
Garnish the serving plate with greens, tomatoes, and chives, if using. Serve the omelet in 1-inch slices.
Optional: Dress the greens, tomatoes, and chives in a bowl first with a drizzle of olive oil, a teaspoon of white wine vinegar, salt, and pepper before garnishing the omelet.