Preheat the oven to 350°F. Lightly grease a 9x13-inch baking dish.
Mix the eggs, oil, milk, and vanilla.
Whisk the flour, granulated sugar, baking powder, and salt.
Combine wet and dry mixtures, then pour half the batter into the dish.
Mix brown sugar and cinnamon; sprinkle half over the batter.
Spread in the remaining batter and top with the remaining cinnamon sugar.
Drizzle melted butter over the top.
Bake 35 to 40 minutes, until a toothpick has a few moist crumbs. Serve warm.