Step 1: Preheat the Oven - Begin by preheating your oven to 400°F (200°C) to ensure even baking.
Step 2: Prepare the Baking Pan - Grease a 9x13-inch baking pan with cooking spray or butter to prevent sticking.
Step 3: Whisk Dry Ingredients - In a large mixing bowl, combine flour, cornmeal, sugar, baking powder, salt, and garlic powder. Whisk until well mixed.
Step 4: Mix Wet Ingredients - In another bowl, whisk together buttermilk, eggs, and melted butter. Ensure the butter isn't too hot.
Step 5: Combine Mixtures - Pour wet ingredients into dry ingredients and stir until just combined; a few lumps are okay.
Step 6: Fold in Corn, Cheese, and Jalapenos - Gently fold in corn, cheddar cheese, and jalapenos until evenly distributed.
Step 7: Bake - Pour batter into the prepared pan and bake for 25-30 minutes, or until golden brown and a toothpick comes out clean.
Step 8: Cool and Serve - Let the cornbread cool for 10 minutes, then cut into squares and serve warm.