Yields 12 cupcakes

Grapefruit Curd:
1/4 cup grapefruit juice
1/4 cup lemon juice
8 egg yolks
Zest of one grapefruit
1 cup sugar
Pinch salt
10 tbsp cold butter (cubed)
1 cup sugar
2 eggs
2 cup flour
2 tsp baking powder
1/2 cup grapefruit juice
2 tbsp grapefruit zest
1/2 cup melted butter
1 tsp vanilla extract
2/3 cup butter (room temp)
4 cups icing sugar
2 tbsp grapefuit juice
1 tbsp lemon juice

  1. For the curd: Combine the grapefruit juice, lemon juice, egg yolks, half of the zest, and sugar in a medium pot. Cook over medium heat, while continuously stirring, until the mixture coats the back of a wooden spoon and is around 160F degrees.
  2. Take off of the heat and then add in the salt and the cubed butter, one cube at a time while stirring.
  3. Pour through a sieve and stir in the rest of the zest. Place in fridge with a piece of saran wrap directly on top to prevent a skin from forming.
  4. Preheat oven to 325F and line cupcake pan with paper liners.
  5. In the bowl of an electric mixer beat together the sugar and eggs until light in colour.
  6. With the mixer on low add in the flour and baking powder.
  7. Add in the grapefruit juice, zest, melted butter, and vanilla and mix until it is just combined, being careful to not over mix.
  8. Scoop batter into prepared cupcake pan and bake for 20~ minutes until the cupcakes are springy to the touch.
  9. Prepare the icing by beating the butter in an electric mixer until it is whipped and slightly fluffy. Add the icing sugar and continue to beat on high for 2-3 minutes. Drizzle in the grapefruit juice.
  10. Make a hole in each of the cupcakes and pipe curd in the centres.
  11. Use a 104 piping tip to pipe the icing ruffles.