May be a little bland...I might spice it up with some roasted red peppers, onion, and feta.

1 tablespoon butter, melted $ Cooking spray $ 2 (6-ounce) packages fresh baby spinach $ 1 1/4 cups (5 ounces) shredded reduced-fat sharp cheddar cheese $ 3/4 cup (3 ounces) shredded Monterey Jack cheese 1 1/3 cups all-purpose flour (about 5 3/4 ounces) $ 1 1/2 cups fat-free milk $ 1 cup egg substitute 1 teaspoon salt 1 teaspoon baking powder 2 teaspoons Dijon mustard 1/4 teaspoon freshly ground black pepper 1/8 teaspoon ground nutmeg 1/8 teaspoon ground red pepper

Preheat oven to 350°.
Pour the butter into the bottom of a 13 x 9-inch baking dish coated with cooking spray; tilt dish to coat. Place spinach evenly in bottom of dish; sprinkle evenly with cheeses.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and remaining ingredients in a medium bowl; stir with a whisk until blended. Pour milk mixture over cheese. Bake at 350° for 40 minutes or until lightly browned. Serve immediately.