Preheat oven to 350 degrees F. Line 2 standard muffin tins with paper liners.

Whisk together flour, cornstarch, cocoa, and salt.

With an electric mixer on medium-high speed, whisk together the sugar and oil until combined. Add the eggs, one at a time, beating until each is incorporated, scraping down sides of bowl as needed. Mix in food coloring, vanilla and rose water.

Reduce speed to low. Add flour mixture in three batches, alternating with the buttermilk, and mixing well after each addition. Stir together the baking soda and vinegar in a small bowl (it will foam) and add the mixture to the batter, mix on medium speed until combined. Stir in the chopped chocolate.

Divide batter evenly among the prepared pans, filling each three-quarters full. Bake 20 minutes or until a toothpick inserted into the center comes out clean, do not over bake. Transfer cupcakes to a wire rack to cool completely.

Meanwhile, make the frosting, using an electric mixer, beat together the cream cheese and butter until smooth and creamy. Slowly beat in the powdered sugar, vanilla bean seeds and rose water until smooth. Add cream to reach your desired consistency.

Once the cupcakes are cool, frost with the cream cheese frosting. Decorate with roses if desired.