Preheat oven to 375°F (190°C). Grease an 8x8-inch baking dish or cast iron skillet.
In a large bowl, whisk cornmeal, flour, sugar, baking powder, salt, paprika, and chili powder.
In a separate bowl, whisk milk, eggs, melted butter, and mayonnaise.
Stir wet ingredients into dry ingredients until just combined.
Fold in corn kernels, shredded cheese, cotija, lime juice, and garlic powder.
Pour batter into prepared dish and smooth the top.
Bake for 25–30 minutes, or until golden and a toothpick comes out clean.
Cool slightly, then top with cotija, cilantro, and a sprinkle of chili powder or Tajín.
Serve warm with lime wedges.