Preheat and prep pans: Heat your oven to 350°F (175°C). Grease and line either two 8-inch round cake pans or one 9x13-inch pan with parchment. Lightly dust with cocoa to prevent sticking.

Whisk dry ingredients: In a large bowl, whisk 2 cups (250 g) flour, 1¾ cups (350 g) sugar, ¾ cup (75 g) cocoa powder, 2 teaspoons baking powder, 1 teaspoon baking soda, and 1 teaspoon salt until well combined.

Add wet ingredients: Add 2 large eggs, 1 cup (240 ml) milk, ½ cup (120 ml) vegetable oil, and 2 teaspoons vanilla. Whisk until smooth and thick—about 30–45 seconds.

Bloom with hot liquid: Carefully pour in 1 cup (240 ml) hot water or hot coffee. Stir gently until the batter is smooth and a bit thin. This step boosts chocolate flavor and moisture.

Pour and bake: Divide batter between the two round pans or pour into the 9x13. Tap pans lightly to pop large bubbles. Bake rounds for 25–30 minutes or a 9x13 for 30–35 minutes, until a toothpick comes out with a few moist crumbs.

Cool completely: Let cakes cool in the pan for 10 minutes, then turn out onto a rack. Remove parchment and cool fully before frosting. Warm cakes will melt frosting.

Make the frosting: Beat 1 cup (227 g) unsalted butter, softened, until fluffy. Sift in 2¾–3¼ cups (330–390 g) powdered sugar and ½ cup (45 g) cocoa powder. Add 1 teaspoon vanilla and 2–4 tablespoons cream or milk, beating until smooth and spreadable. Add a pinch of salt to balance sweetness.

Frost the cake: For layers, level domes if needed. Spread a generous layer of frosting between cakes, then coat the sides and top. For a 9x13, frost right in the pan for easy serving.

Decorate: Add sprinkles, chocolate chips, or colorful candies. Press them gently into the frosting so they stick.

Rest before slicing: Let the cake sit 20–30 minutes so the frosting sets slightly. Slice with a warm knife for clean cuts.