Spinach Pierogi Pizza

10oz Can Pillsbury -Refrigerated All -Ready Pizza Crust
9oz Pkg Green Giant Harvest -Fresh Frozen Spinach, -thawed, squeezed to -drain
1/2c Chopped onion
2tb Butter
1-1/2c Mashed potatoes
2tb Oil
1/2ts Garlic salt
1c Shredded mozzarella -cheese
1/2 c Shredded Cheddar cheese
1sm Onion, sliced, separated -into rings

Heat oven to 425 degrees. Grease 13 x 9" pan. Unroll dough and place in greased pan; starting at center, press out with hands. Bake for 7 to 9 minutes or until light golden brown. Meanwhile, in large skillet cook spinach and chopped onion in butter until onion is crisp-tender. Stir in potatoes; mix well. In small bowl, combine oil and garlic salt; mix well. Brush over partially baked crust; top with spinach mixture. Sprinkle with mozzarella and then Cheddar cheeses; top with onion rings. Bake for another 15 to 20 minutes or until cheese is melted and edges of crust are golden brown.