Squeeze the water out of the spinach and place in a large bowl.
Add egg, ricotta cheese, and sour cream and stir until evenly mixed. Make sure there are no clumps of spinach.
Add mozzarella cheese, parmesan cheese, salt, onion powder, garlic powder, Italian seasoning, red pepper flakes, and olive oil. Mix well.
Mix in 1 cup of flour. Mix in the remaining flour.
Shape into 1 1/2-inch balls. You should get 30 to 36 total.
Pour about 1 1/2 to 2 inches of oil into a Dutch oven. Heat oil to 350 degrees.
Combine bread crumbs and salt in a pie plate. Roll balls in bread crumb mixture.
Fry 6 to 8 balls at a time for 3 to 4 minutes. Remove with a slotted spoon and set on a paper towel-lined plate.Note: To keep them warm, place on a rimmed baking sheet in a 200 degree oven.