Combine flour, cornmeal, kosher salt, baking soda, and baking powder in a large bowl and whisk ingredients together. In a separate bowl, whisk together melted butter, oil, eggs, sugar, and milk. Whisk until smooth and al lumps are gone. (You can use a hand mixer to do this)
Spray a muffin pan with oil and line with muffin cups/liners. Scoop about 2-3 tbsps batter into each liner. Bake for 20-25 minutes, until a toothpick comes out clean.
Combine butter, maple syrup, and ground cinnamon in a small bowl. Drizzle on top of corn muffins.