01 -
Preheat oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan or line with parchment paper.
02 -
In a medium bowl, whisk together flour, baking powder, and salt until well mixed.
03 -
In a large mixing bowl, beat unsalted butter and granulated sugar with an electric mixer on medium speed until light and fluffy, about 3 minutes.
04 -
Add eggs one at a time, beating well after each addition, then mix in the vegetable oil until fully incorporated.
05 -
Reduce mixer speed to low. Add milk and vanilla extract, mixing until combined. Scrape down the sides of the bowl as needed.
06 -
Add the flour mixture to the wet mixture in two parts, mixing on low until just combined. Do not overmix.
07 -
Gently fold in 1 cup of mini chocolate chips with a spatula, ensuring even distribution.
08 -
Pour the batter into the prepared pan and smooth the surface. Bake in the preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
09 -
Remove the cake from the oven and allow it to cool in the pan on a wire rack for at least 30 minutes before frosting.
10 -
In a bowl, blend sifted powdered sugar, vanilla extract, and heavy cream, mixing until smooth and spreadable.
11 -
Spread frosting evenly over the cooled cake. Sprinkle 1/4 cup mini chocolate chips on top for garnish.
12 -
Slice and serve as desired. Store leftovers in an airtight container at room temperature for up to 3 days.