Preheat the oven. Set the oven to 425°F (220°C). Lightly coat a baking dish or baking sheet with nonstick cooking spray.
Prepare the ingredients. Thaw the frozen spinach and squeeze out as much excess moisture as possible. Make sure your chosen sausage or bacon is fully cooked and chopped into small pieces.
Whisk the eggs. In a medium bowl, whisk together the liquid egg whites or whole eggs, milk, garlic pepper seasoning, and cayenne pepper.
Scramble the eggs. Lightly coat a large skillet with cooking spray and heat over medium-high heat. Add the egg mixture and cook, stirring gently, until the eggs are nearly set.
Add the spinach and meat. Stir the drained spinach and cooked sausage or bacon into the eggs. Mix until evenly combined and continue cooking until the eggs are set. Remove from the heat.
Divide the filling. Place an egg roll wrapper on a clean work surface. Spoon one-eighth of the egg mixture into the center.
Add the cheeses. If using Monterey Jack, sprinkle approximately 2 tablespoons over the filling. Add ½ tablespoon grated Asiago cheese.
Roll the wrapper. Lightly moisten the wrapper edges with water. Fold in the sides, then roll tightly into an egg roll shape. Press the edges to seal.
Repeat. Assemble the remaining seven egg rolls, dividing the filling and cheese evenly. Arrange the rolls seam-side down on the prepared baking dish or sheet.
Spray and bake. Lightly spray the tops of the egg rolls with cooking spray. Bake for 8 minutes.
Flip and finish baking. Carefully turn each egg roll over and bake for another 8 minutes, or until the wrappers are starting to crisp and turn golden brown.
Cool and serve. Remove from the oven and allow the egg rolls to cool for approximately 1 minute before serving warm.