Cold, Bright, and Unmistakably Grapefruit-y: Grapefruit Cake Bars

I added Sarah Kieffer's "Grapefruit Cake Bars" to my to-bake list when I first flipped through 100 Cookies; I love grapefruit and the dainty bars covered in white glaze looked so pretty in the cookbook photo. And as I read through the recipe, I was happy to see that the it calls for an ingredient that I have on hand but rarely get to use: grapefruit liqueur. 
A while ago my husband and I were on a walk in Capitol Hill and we decided to pop into Schneider's wine store (this was in pre-pandemic days). As my husband browsed through the wine, I went straight to the section with cordials and liqueurs -- I'm always looking for things I can use to flavor buttercream (and in fact, since I don't drink alcohol at all, I buy it exclusively for baking applications). A store employee asked if he could help and I explained that I was just looking for liqueur to flavor frosting. His first suggestion was a peanut butter whiskey. That sounded awful, so I took a hard pass. Next, he pointed me to to a selection of Vedrenne liqueurs. The pink color of the Pamplemousse Rose (pink grapefruit) jumped out at me, so I bought a bottle.

I have used the grapefruit liqueur to flavor a fair amount of buttercream, but before this cake I had never come across another recipe that called for it. I was delighted to find another use for it. But if you're interested in making this cake, no worries -- it's listed as an optional ingredient in both the cake and the glaze, so there's no need to go out and buy the liqueur just to try the recipe.
This cake requires a bit of work, only because you need to prep the fresh grapefruit. First, you zest a grapefruit and a lemon, and rub the zests into granulated sugar until the sugar is damp and fragrant. Then you cut the grapefruit into supremes (collecting all of the juice), break up the grapefruit segments into pieces about 1/2-inch wide, and set them aside. Once all this prep work is done, the cake comes together quickly. You beat room temperature butter with the zest/granulated sugar until light and fluffy; add eggs, followed by vanilla, grapefruit liqueur, and sour cream; mix in the dry ingredients (flour, salt, and baking soda); and fold in the grapefruit pieces and all of the juice. You pour the batter into a parchment-lined pan and bake.
While the cake is baking, you make a glaze by combining grapefruit zest, powdered sugar, salt, grapefruit juice, grapefruit liqueur, and lemon juice. When the cake is done baking, you let it cool for five minutes, and then poke holes all over the surface and pour over half over the glaze. You let that glaze soak in and set, and then add the remaining glaze. After the cake is completely cooled, you chill it before slicing.
My grapefruit had light yellow-orange zest but pink flesh, and you could see pink pieces of grapefruit in the cake after I sliced it. I loved this cake so much. It tasted amazing cold, straight out of the fridge (where you need to store it), and the texture was dense but moist where the glaze had soaked in. The cake was very grapefruit-y, which I really appreciated -- I have made several grapefruit desserts before and in general, I think it's a difficult flavor to express clearly in a cake. But I suppose there is so much grapefruit in this cake -- flesh, juice, zest, and liqueur in the cake; and juice, zest, and liqueur in the glaze (with lemon playing a supporting role) -- that the flavor is bright, clear, and unmistakable. If you want a grapefruit-centric cake, this is all you could ask for.
Recipe: "Grapefruit Cake Bars" from 100 Cookies by Sarah Kieffer.


Raylene said… sounds delicious! Until I started reading your blog, I had no interest in baking with grapefruit, but you make it look so delicious, I'm going to have to give it a try.

I am so curious. How far have you gotten through 100 Cookies? How many recipes have you made so far???
It's funny you ask this, because I was taking a quick count just this morning (because I made another three recipes from the cookbook just this week). I think I'm up to 24 now, and I'm not stopping anytime soon!!