1. Preheat the oven to 350°F and lightly grease an 8-inch square baking pan.

2. In a medium bowl, whisk together the flour, cocoa powder, granulated sugar, baking soda, and salt.

3. In another bowl, whisk together the buttermilk, vegetable oil, egg, vanilla extract, red food coloring, and white vinegar.

4. Pour the wet ingredients into the dry ingredients and mix just until smooth.

5. Spread the batter into the prepared pan and bake for 18 to 22 minutes, or until a toothpick inserted in the center comes out clean.

6. Let the cake cool completely, then crumble it into fine, soft crumbs.

7. In a large bowl, beat the softened cream cheese with the powdered sugar and vanilla extract until smooth.

8. In a separate bowl, whip the heavy whipping cream until soft peaks form.

9. Fold the whipped cream gently into the cream cheese mixture until the mousse is light and fluffy.

10. Spoon a layer of red velvet crumbs into the bottom of 6 dessert cups.

11. Add a layer of vanilla mousse over the crumbs, smoothing it lightly.

12. Repeat the layers, finishing with mousse on top.

13. Chill the dessert cups for at least 2 hours.

14. Garnish with extra red velvet crumbs and fresh raspberries before serving.