Spinach and Cheddar Rolled Omelet

Spinach and Cheddar Rolled Omelet
Ingredients
olive oil, for pan
1 cup milk
1/3 cup all-purpose flour
8 large eggs
1 Tbsp Dijon mustard
coarse salt and ground pepper
1 package frozen spinach, thawed and squeeze dry
1 1/2 cups shredded cheddar, 6 ounces (I used a mild, white cheddar)

Instructions
-Preheat oven to 350 F. Brush a 10 by 15 inch rimmed baking sheet or jelly-roll pan with oil. Line bottom of pan with parchment, leaving a 1-inch overhang on the two shorter sides. Brush parchment with oil.

-In a bowl, whisk together milk and flour. Add eggs, mustard, 1 tsp salt, and 1/4 tsp pepper; whisk to combine. Pour into pan. Sprinkle spinach over top in an even layer.

-Bake until edges of omelet are set, 10 to 12 minutes. Sprinkle with cheddar; bake until cheese has melted, 2 to 4 minutes.
Beginning at one shorter end, lift parchment and roll up the omelet tightly, peeling back parchment as you go. Slice and serve.