1 cup unsalted butter, softened
2 cups cake flour, sifted
5 large eggs
1 tsp vanilla
1 tbs grapefruit zest
1 ¼ cups sugar
3 tbs freshly-squeezed grapefruit juice
1 cup confectioners’ sugar
Butter and flour an 8-cup loaf pan. Set aside. Preheat oven to 325 degrees.
In the bowl of an electric mixer, fitted with the paddle attachment, cream butter. In a large bowl, whisk together eggs and flavourings. Gradually whisk sugar into eggs. Add egg/sugar mixture to butter, 1 tbs at a time, beating until light and fluffy; 3 to 4 minutes.
Add flour in three parts, mixing on low and scraping down sides of bowl as necessary. Scrape batter into prepared loaf pan. Bake until cake pulls away from sides of pan; 50 to 55 minutes. Let cool 5 minutes, then turn out onto a cooling rack to cool completely before glazing.
Using an electric mixer, beat together grapefruit juice and confectioners’ sugar until smooth. Mixture should flow easily, but not be too runny (add more sugar if necessary). With cake on cooling rack, set over a baking tray to catch run-off, pour glaze over cake, letting it drizzle down the sides. Allow glaze to set.