Blind bake the pie crust at 350 degrees for approximately 15 minutes, or until just starting to brown using pie weights or beans.
Chop the tomatoes and place in a colander in the sink sprinkled with a bit of salt, to allow liquid to drain.
Meanwhile, saute onion in oil (1 tablespoon) in a medium skillet on medium high until browned (2-3 minutes). Add spinach and turn the heat to medium- saute until wilted and most of the liquid has evaporated (5-7 minutes). Season with salt, pepper, and crushed red pepper.
Meanwhile, mix together mayonnaise (1/2 cup), mozzarella (1.5 cups), hot sauce (1 tablespoon), and salt and pepper to taste in a small bowl.
Pat tomatoes dry with a paper towel and add to spinach mixture.
Spread the spinach mixture in the half-baked pie crust and top with mayo mixture.
Bake at 350 for 35-40 minutes, or until browned and bubbly.
Allow to sit for at least 10 minutes before cutting into the pie.
This pie can be made in advance and served at room temperature or cold. You can also pre blind-bake the crust, pre-cook the filling, and pre-mix the topping for easy day of assembly.
The provided nutrition information does not include any added sodium from seasoning to taste, any optional ingredients, and it does not take brands into account. Feel free to calculate it yourself using this calculator or by adding the recipe to Yummly.