Preparation
Preheat your oven to 350°F (175°C) and lightly grease a 1-quart baking dish.
In a medium skillet, melt the butter over medium heat.
Add the precooked shrimp, minced garlic, and red pepper flakes.
Sauté for 2-3 minutes until fragrant and the shrimp are heated through.
Remove from heat and set aside.
In a large bowl, combine the mayonnaise, sour cream, garlic powder, 3/4 cup (960 ml) of the Cheddar cheese, and 1 cup (240 ml) of the Parmesan cheese.
Stir until well blended.
Gently fold in the chopped artichoke hearts, the sautéed shrimp mixture, and the sliced scallions (reserving some greens for garnish).
Pour the mixture into the prepared baking dish and spread evenly.
Top with the remaining 1/4 cup (960 ml) Cheddar and 1/4 cup (960 ml) Parmesan cheese.
Bake for 25-30 minutes, or until the dip is hot, bubbly, and golden brown on top.
Let it rest for 5 minutes before garnishing with the remaining scallion greens and serving hot.