Preheat the oven to 350 degrees F. Grease a 9x13 baking pan with nonstick cooking spray.

In a medium mixing bowl, add the flour, cocoa powder, baking powder, baking soda, and salt. Whisk until well combined.

In a large bowl, add the oil, eggs, milk, vanilla and sugar. Whisk until well mixed.

Add the dry ingredients into the bowl of wet ingredients, whisking until the flour is fully incorporated.

Pour the cake batter into the prepared baking pan and spread evenly to the edges of the pan.

Place in the preheated oven and bake for 30-35 minutes or until a toothpick inserted in the center of the cake comes out clean or with moist crumbs.

Place the cake on a cooling rack and allow to sit for about 15 minutes before running a knife along the edges of the cake.

Using the same knife, or a small skewer, poke holes in the top of the cake.

While the cake is cooling for the 15 minutes, add the sweetened condensed milk, heavy cream and chocolate milk in a medium bowl. Whisk until combined.

Pour the milk mixture over the entire cake while it’s still warm.

Place the cake in the refrigerator for at least 30 minutes and up to 2 hours to allow it to chill and absorb the liquid.

In a large bowl, add the heavy whipping cream, powdered sugar, vanilla and cocoa powder. Beat using a hand mixer on medium speed until stiff peaks form.

Spread the topping in an even layer over the top of the chilled cake.

Dust with cocoa powder and sprinkle mini chocolate chips if desired.

Store any leftovers in an airtight container for up to 3 days in the refrigerator.