Preheat oven to 350 degrees F. Lightly grease a 9x13" baking pan with cooking spray and set aside.

In a large bowl whisk together the eggs, sugar, milk, vegetable oil and vanilla extract until combined.

Add in 3 cups all-purpose flour, baking powder and salt and whisk until combined. Set aside.

Combine the topping ingredients (brown sugar, cinnamon, cold butter and flour) in a medium bowl and use clean hands to pinch the butter into the brown sugar and flour, creating a crumbly and coarse topping.

Pour half of the cake batter into the prepared baking pan and then sprinkle 1/3 of the topping over the batter. Pour the remaining cake batter over the top, then sprinkle the remaining topping over the batter.

Bake the cake for 40 to 50 minutes, until a toothpick inserted in the center comes out clean. Let the cake cool slightly before serving. Serve warm or let cool completely.