1-Prepare the baking pan and preheat the oven: First, preheat your oven to 350°F and coat a 9×13-inch pan with cooking spray, olive oil, or butter to prevent sticking. This step sets the stage for a smooth baking process that takes about 30 minutes.

2-Make the batter and bake the cake: In a large bowl, combine 2 cups all-purpose flour, 2 cups granulated sugar, 1 cup unsweetened cocoa powder, 2 teaspoons baking powder, 1 teaspoon baking soda, 1/2 teaspoon ground cinnamon, and a pinch of kosher salt. Then, add 2 cups milk, 1/2 cup vegetable oil, 2 large eggs, and 2 teaspoons vanilla extract, whisking until the batter is smooth and lump-free. Pour this into your prepared pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

3-Prepare the milk mixture and soak the cake: After baking, let the cake cool for 10 minutes. In another bowl, whisk together the remaining 1 cup milk, 8 ounces sweetened condensed milk, and 6 ounces evaporated milk. Gently loosen the cake from the pan sides, poke holes all over it with a fork or skewer, and slowly pour the milk mixture over the top. Cover and refrigerate for at least 2 hours to let it absorb and cool fully.

4-Make the whipped topping and finish the cake: While it’s chilling, beat 1 cup heavy cream with 1 1/2 tablespoons granulated sugar, 1 tablespoon unsweetened cocoa powder, and 1/4 teaspoon vanilla extract until soft peaks form, then refrigerate. Once cooled, spread the whipped topping over the cake and garnish with chocolate shavings.