Spray a shallow baking dish or small oven-safe skillet with nonstick cooking spray; set dish aside.
Place thawed spinach in a large bowl and drain excess liquid. Using several paper towels, press the spinach firmly to drain as much liquid as possible. Coarsely chop the dried spinach and return it to the bowl.
Add softened cream cheese, chopped artichoke hearts, sour cream and mayonnaise; stir until well combined.
Add garlic, onion powder, paprika, pepper, salt, cheddar cheese and 1 cup of Monterey Jack cheese; stir until well combined.
Spread the spinach dip into the prepared baking dish. Sprinkle the remaining ¾ cup of Monterey Jack cheese evenly on top.
Bake for 30 minutes, or until mixture is heated through and cheese on top has fully melted.
{Optional} Broil for 2-3 minutes, or until cheese on top begins to turn golden brown.
Remove dish from oven and top with chopped parsley.
Serve warm with toasted baguette slices, crackers, pita chips or veggies.