• Preheat the oven to 325 degrees F. Spray a 9x9 inch pan with nonstick baking spray.
• In a small bowl, whisk together the flour, baking powder, salt and baking soda.
• In a large bowl, stir together the sugar and grapefruit zest with a fork until combined.
• To the same large bowl, whisk in the butter. Stir until the butter and sugar mixture is smooth. Whisk in the eggs, one at a time. Whisk in the greek yogurt and vanilla extract.
• Add the dry ingredients and stir until just combined. Pour the batter in the greased 9x9 inch pan.
• Bake for 30 to 32 minutes or until the cake is set. Cool completely, then drizzle the glaze on top.

grapefruit glaze

• Whisk together the sugar and juice until combined, smooth and drizzle-able. If it’s too thick, add more grapefruit juice 1 teaspoon at a time. If it ends up too thin, stir in more powdered sugar until it is thick enough. Stir in the zest. Pour the glaze over the cake and spread it to cover the top. Let it sit for 10 minutes before slicing and serving!