Preheat oven to 350°F and grease a 9x9 casserole dish.
Squeeze out as much liquid as possible from the defrosted spinach.
In a large bowl, mix the cream cheese, sour cream, and mayonnaise until well combined.
Add the spinach, artichoke hearts, crab meat, green onions, Parmesan cheese, and remaining mozzarella (reserving 1/4 cup for topping) to the bowl. Gently fold everything together until well mixed.
Transfer the mixture into the greased 9x9 casserole dish. Top with the reserved 1/4 cup of mozzarella cheese and a light sprinkle of smoked paprika.
Place the dish in the preheated oven and bake for 20-25 minutes.
After baking, set the oven to broil and let the dish cook for an additional 1-2 minutes, until the top is golden and bubbly.
While the dip is baking, place the sliced baguette pieces in a single layer on a large baking sheet. Cut the end off the garlic clove and rub it on the top side of each bread slice. Brush with olive oil and sprinkle lightly with Old Bay seasoning.
Once the dip is done, place the prepared bread under the broiler for 1-2 minutes until it reaches your desired color.
Serve the hot crab dip with the freshly baked bread slices.