Preheat Oven:

Set your oven to 375°F (190°C).
Mix Ingredients:

In a large bowl, combine the cream cheese, sour cream, and mayonnaise until smooth. Stir in the cheddar, Monterey Jack, and Parmesan cheeses, reserving a little cheddar for topping.
Add the corn, jalapeño, red bell pepper, green onions, garlic powder, salt, and pepper. Mix until well combined.
Assemble the Dip:

Transfer the mixture to a greased baking dish or cast-iron skillet. Spread evenly and sprinkle the reserved cheddar cheese on top.
Bake:

Bake for 20-25 minutes, or until the dip is hot and bubbly and the top is golden brown.
Serve:

Garnish with chopped cilantro if desired. Serve warm with tortilla chips, crackers, or veggie sticks.
Prep Time: 10 minutes | Cook Time: 25 minutes | Total Time: 35 minutes
Servings: 6-8