Gently press the crust into the lined pan. Ensure crust an even thickness throughout. Bake for 20 minutes.
Fold together sugar, flour, and baking powder. Add the eggs to the bowl and then using a hand mixer beat batter. Add freshly squeezed grapefruit juice and grapefruit zest.
Bake for another 25 minutes. After the bars have slightly cooled, place them in the freezer for 2 hours to chill.
After the bars have chilled, allow them to sit at room temperature for 15-20 minutes before slicing and serving. Enjoy!