INGREDIENTS
1 stick
butter, at room temp
3/4 cup
sugar
1
egg yolk
1
large grapefruit, zested and juiced
1 1/2 cups
flour
3/4 cup
cake flour
1/2 tsp
salt
1 tsp
baking powder
1 stick
butter, at room temp
3 cups
powdered sugar
salt
1 tbsp
grapefruit zest (unpacked)
2 1/2 tbsp
grapefruit juice
1
drop red food coloring (optional)