Preheat the oven to 350°F and line a 9x13 pan with parchment paper with the ends or the paper hanging over the edges. (This will allow you to lift out the bars when they’re done for easier cutting.)
To make the crust, mix together the butter and sugar until creamy and well blended. Mix in the vanilla extract and egg until well blended. Mix in the flour, baking powder, salt, pecans, and grapefruit zest until well blended and a thick and pliable dough much like a cookie dough, is formed. Pat the dough evenly into the bottom of the pan.
To make the filling, mix the cream cheese until smooth and fluffy, then blend in the eggs, vanilla extract, Ruby Red grapefruit juice, Ruby Red grapefruit zest, confectioner’s sugar, and salt. Blend until smooth.
Pour the filling over the crust then bake uncovered for 45-50 minutes or until the top of the squares are lightly browned. Allow to rest for 20 minutes before slicing. Can also chill before slicing, as they’re also very delicious cold.