Preheat the oven to 350°F. Oil the bottom and sides of an 8-inch cast iron skillet or similar. Set aside.
Thaw the spinach and squeeze to remove as much moisture as possible.
In a medium size bowl, whip together the cream cheese, mayonnaise, heavy cream, garlic salt, onion powder and black pepper. Whip until creamy and combined around 1-2 minutes.
By hand mix in the spinach, green onion, bacon and 1 1/2 cup shredded cheese. Pour into the skillet.
Top with the remaining cheese. Bake for 30 minutes or until bubbly.
Serve with pita crisps, tortilla chips or crackers for dipping.