Preheat oven to 350⁰F. Grease and line a 9” round cake pan with parchment paper. Set pan aside.
In a large bowl, mix together the melted butter, oil, sugars, honey, coffee, egg, and vanilla until fully combined.
Fold beet purée into liquid ingredients.
In a medium bowl, carefully whisk together dry ingredients – flour, cocoa powder, baking soda, salt, and cornstarch.
Add half of the dry ingredients to the wet, stirring with a spatula to integrate, then add the remaining dry ingredients and stir until combined.
Pour batter into prepared cake pan. Use a spatula to smooth the top of the batter, then place the cake in the preheated oven.
Bake cake for 25-30 minutes, removing from the oven when a toothpick inserted into the center comes out of the cake mostly crumb-free.
Cool the cake in the pan for 20 minutes, then run a knife along the edge of the pan and invert it on a cooling rack. Leave the cake to cool completely.
Once cooled, ice cake or dust with powdered sugar as desired and serve.