Preheat your oven to 375°F (190°C). This step helps create a perfectly bubbly and golden top for your dip.
Prepare the shrimp: In a skillet over medium heat, add 1 tablespoon of olive oil. Once hot, add the chopped shrimp (1/2 lb) and sauté until pink and cooked through, about 3-4 minutes. Remove from heat and set aside.
Create the base: In a mixing bowl, combine 8 oz softened cream cheese, 1/2 cup sour cream, and 1/2 cup mayonnaise. Mix until smooth and creamy.
Incorporate the seafood and vegetables: To the bowl, add the cooked shrimp, lump crab meat (1/2 lb), thawed and drained spinach (1 cup), minced garlic (2 cloves), chopped onion (1 small), Old Bay seasoning (1 tsp), and salt and pepper to taste. Stir until well combined.
Transfer to baking dish: Spread the mixture evenly into an oven-safe baking dish, smoothing out the top.
Finish with cheese: Sprinkle 1 cup of shredded mozzarella on top of the mixture for a cheesy finish.
Bake your dip: Place the baking dish in the preheated oven and bake for 20-25 minutes, or until the dip is bubbly and the cheese is golden brown.
Serve and enjoy: Let it cool slightly before serving with tortilla chips, crackers, or slices of bread for dipping.