These Cheesy Spinach Bacon Appetizer Bars are a warm, crowd-pleasing appetizer made with refrigerated pizza crust, crispy bacon, sautéed red onion, spinach, and two kinds of cheese. Baked in a sheet pan and cut into easy squares, they’re perfect for holiday gatherings, potlucks, game day, or cozy cold-weather entertaining.
Preheat your oven to 425 degrees F. Lightly spray a 10 x 15-inch sheet pan with cooking spray.
Unroll the pizza dough into the prepared pan and gently press it out with your hands so it covers the bottom evenly. Bake for 10 minutes, or until the crust is lightly golden. It may shrink slightly as it bakes.
While the crust is in the oven, cook the bacon in a medium skillet over medium heat until crisp. Transfer the bacon to a paper towel-lined plate to drain. Once cool enough to handle, crumble and set aside.
Pour off most of the bacon drippings, reserving about 1 tablespoon in the skillet. Add the chopped red onion and cook over medium heat until crisp-tender, stirring occasionally.
Once the crust is lightly golden, remove it from the oven. Evenly sprinkle the crumbled bacon and sautéed onions over the crust. Top with the well-drained spinach, garlic powder, cheddar cheese, and mozzarella cheese.
Return the pan to the oven and bake for 8 to 10 minutes, or until the crust is deep golden brown and the cheese is melted and bubbly. Add salt and pepper to taste.
Let cool slightly, then cut into squares and serve warm.