Preheat oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper.

In a large bowl, whisk flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Add eggs, milk, oil, and vanilla. Mix until smooth.

Gradually pour in hot water while stirring—batter will be thin.

Divide evenly among pans. Bake for 25-30 minutes, or until a toothpick comes out clean.

Cool cakes in pans for 10 minutes, then transfer to a wire rack to cool completely.

Heat sugar in a saucepan over medium heat, stirring occasionally until melted and amber-colored.

Add butter and whisk until fully melted.

Slowly pour in heavy cream while stirring—mixture will bubble.

Remove from heat, stir in vanilla and salt. Let cool slightly before using.

Beat butter until creamy. Gradually add powdered sugar, caramel sauce, cream, and salt.

Whip until light and fluffy (3-4 minutes).

Place one cake layer on a plate. Spread ¼ cup caramel sauce, then a layer of frosting.

Repeat with remaining layers.

Frost the outside and drizzle extra caramel on top.