Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. In a large bowl, sift together the flour, sugar, cocoa powder, baking soda, and salt. In another bowl, mix together the oil, buttermilk, eggs, red food coloring, vanilla extract, and vinegar. Combine the wet and dry ingredients, mixing until just combined. Divide the batter between the prepared pans and bake for 25-30 minutes or until a toothpick comes out clean. Let them cool completely.

Mousse Preparation

Make the Cheesecake Mousse

In a mixing bowl, beat the cream cheese until smooth. Gradually add powdered sugar and vanilla, mixing until well combined. In another bowl, whip the heavy cream until soft peaks form. Gently fold the whipped cream into the cream cheese mixture until fully incorporated. Chill in the refrigerator.

Glaze and Crumble Preparation

Prepare the Red Chocolate Glaze

In a small saucepan, heat the heavy cream until just simmering. Remove from heat and add chopped dark chocolate and red food coloring. Stir until smooth and glossy. Let it cool slightly.

Make the Chocolate Crumble

Preheat the oven to 350°F (175°C). In a bowl, mix together flour, cocoa powder, sugar, and melted butter until crumbly. Spread on a baking sheet and bake for 10-12 minutes until crisp. Let cool.

Assembly

Assemble the Cake

Once the cake layers are completely cooled, place one layer on a serving dish. Spread half of the cheesecake mousse over the first layer, then top with the second cake layer. Spread the remaining mousse on top. Drizzle the red chocolate glaze over the mousse. Finish by sprinkling chocolate crumble on top. Chill in the refrigerator for at least 2 hours before serving.