Preheat oven to 170°C and line a 12-cup muffin tin with paper liners.
Blend beetroot, eggs, vinegar, and olive oil until smooth.
In a separate bowl, mix flour, sugar, baking powder, and cocoa powder.
Combine wet and dry mixtures until just incorporated, avoiding overmixing.
Divide batter evenly among muffin cups.
Bake for 25 minutes or until a toothpick inserted in center comes out clean.
Cool in pan for 5 minutes before transferring to wire rack.
Decorate with melted chocolate or edible flowers once cooled.