Preheat the oven to 350 degrees. Lightly spray an 8-inch spring-form pan with cooking spray.
In small bowl, combine flour, cocoa, almonds, salt & baking soda, set aside.
Using a standing or hand-held mixer at medium speed, beat the eggs and sugar for 4 full minutes until pale and fluffy. On low speed, beat in the grated beets, followed by dry ingredients. Add the buttermilk and coffee, and beat until batter is smooth.
Pour into pan and place in middle of hot oven, bake for 30 minutes. Test with toothpick for doneness; bake an additional 5 minutes if needed.
Cool for 10 minutes and unmold onto cooling rack. Cool on rack until cold. To make icing, prepare a double boiler. Combine all the icing ingredients and gently stir until chocolate is smooth; continue stirring until mixture thickens.
Pour icing liberally over the top of cake and let it drip down the sides. Transfer onto a plate or cake stand for serving and garnish with rose petals.