Preheat oven to 350 F degrees. Spray a 9" pie plate or 9" cast iron skillet with non-stick cooking spray and set aside.
Add artichoke hearts to a mesh sieve and lay a few paper towels on top. Press down to remove any excess liquid. Transfer artichokes to a cutting board and chop. Set aside.
To a small skillet, add bacon strips and cook over MED to MED-LOW heat until bacon is crisp and brown. Remove to a plate, reserving drippings, and add diced onion to the skillet with the reserved bacon drippings. Raise heat to MED-HIGH and cook 3-5 minutes, until soft and starting to brown. Add spinach and garlic to the skillet and cook another minute, until spinach is wilted. Set aside.
To a large mixing bowl, add sour cream and flour. Stir together, then add in mayo, chopped artichoke hearts, roasted red peppers, bacon, and cooked spinach and onion mixture. Stir together, then add in mozzarella cheese, 1/2 cup asiago cheese, and black pepper. Stir to combine.
Transfer mixture to prepared baking dish/skillet and top with remaining 1/4 cup asiago cheese. Bake, uncovered, for 30 minutes, until heated through and lightly browned.
Serve with toasted baguette slices, pita chips, sturdy tortilla chips or veggies.