**Preheat the Oven:** Preheat your oven to 375°F (190°C).
**Mix the Base Ingredients:** In a large mixing bowl, combine the cream cheese, mayonnaise, and sour cream. Use an electric mixer or whisk to beat until smooth and creamy.
**Add Flavorings:** Stir in the lemon juice, Worcestershire sauce, Old Bay seasoning, Dijon mustard, garlic powder, Parmesan cheese, and cheddar cheese until well combined.
**Fold in the Crab:** Gently fold in the crab meat, being careful not to break up the lumps too much.
**Transfer to Baking Dish:** Spoon the mixture into a greased baking dish and spread it out evenly.
**Top with Cheese:** Sprinkle additional shredded cheddar cheese over the top.
**Bake:** Bake in the preheated oven for 20-25 minutes, or until the dip is hot and bubbly.
**Garnish and Serve:** Remove from the oven, garnish with chopped green onions if desired, and serve immediately with crackers, bread, or vegetables.