When winter citrus season arrives, there’s nothing quite like the vibrant burst of ruby red grapefruit to brighten up your kitchen. These Ruby Red Grapefruit Bars combine the best of both worlds: a buttery, crumbly shortbread base topped with a silky, tart grapefruit curd that practically glows with sunny color. The beautiful pink hue comes naturally from the ruby red grapefruit juice and zest, creating bars that are as stunning to look at as they are delicious to eat. Perfect for afternoon tea, potluck gatherings, or whenever you need a citrusy pick-me-up, this recipe yields 16 generous squares that will disappear faster than you can say “more, please.”
Ingredients
For the shortbread crust:
- 2 cups all-purpose flour
- 1/2 cup powdered sugar
- 1/2 teaspoon salt
- 1 cup unsalted butter, cold and cubed
For the grapefruit filling:
- 4 large eggs
- 1 1/2 cups granulated sugar
- 1/4 cup all-purpose flour
- 1/4 teaspoon salt
- 2/3 cup fresh ruby red grapefruit juice
- 2 tablespoons ruby red grapefruit zest
- 4 tablespoons unsalted butter, melted
For finishing:
- 1/2 cup powdered sugar for dusting
Preparing Your Pan and Oven
Preheat your oven to 350 degrees Fahrenheit. Line a 9×13 inch baking pan with parchment paper, leaving some overhang on the sides for easy removal later. This little trick will save you from any sticking disasters and make cutting your bars much cleaner. Lightly grease the parchment paper with butter or cooking spray.
Making the Shortbread Base
In a large mixing bowl, whisk together the flour, powdered sugar, and salt until well combined. Add the cold, cubed butter to the flour mixture. Using a pastry cutter, two knives, or your clean hands, work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining. The key here is keeping the butter cold, which creates that tender, flaky texture we love in shortbread.
Press the mixture firmly and evenly into the bottom of your prepared baking pan. Use the bottom of a measuring cup or your hands to create a smooth, compact layer. The crust should reach all corners and be level across the pan.
Bake the crust for 18-20 minutes, until the edges are just beginning to turn golden brown. The center should look set but not deeply colored. Remove from the oven and let it cool slightly while you prepare the grapefruit filling.
Creating the Grapefruit Curd Topping
In a medium bowl, whisk the eggs until smooth and well beaten. Add the granulated sugar and whisk vigorously until the mixture is pale and slightly thickened. This usually takes about 2-3 minutes of steady whisking.
In a separate small bowl, whisk together the flour and salt, then gradually add this to the egg mixture, whisking constantly to prevent lumps. Slowly pour in the fresh grapefruit juice, grapefruit zest, and melted butter, whisking continuously until the filling is completely smooth and well combined.
The filling should have a beautiful pink tint from the ruby red grapefruit juice. If your grapefruit isn’t quite ruby enough, don’t worry – the bars will still taste amazing, just with a lighter color.
Assembling and Baking
Pour the grapefruit filling over the warm shortbread crust, spreading it gently to reach all corners. The filling will be quite liquid, which is exactly what you want. As it bakes, it will set into that perfect curd-like consistency.
Return the pan to the oven and bake for 22-25 minutes, until the filling is set around the edges but still has a slight jiggle in the center when you gently shake the pan. The top should look glossy and smooth, not cracked or overly browned.
Cooling and Finishing
Remove the bars from the oven and place the pan on a wire rack to cool completely. This step requires patience, as cutting the bars too early will result in a messy, runny filling. Allow at least 2 hours for complete cooling, or refrigerate for 1 hour if you’re in a hurry.
Once completely cool, use the parchment paper overhang to lift the entire slab out of the pan and onto a cutting board. Using a sharp knife, cut into 16 squares, wiping the blade clean between cuts for the neatest presentation.
The Perfect Finish
Just before serving, dust the bars generously with powdered sugar using a fine-mesh sieve. This not only adds a lovely visual contrast against the pink filling but also provides a subtle sweetness that perfectly balances the tart grapefruit.
Storage and Serving Tips
These bars are best served chilled or at room temperature and will keep covered in the refrigerator for up to four days. The flavors actually improve after the first day, as the grapefruit filling has time to fully set and develop its bright, tangy character. For the cleanest cuts, use a sharp knife and clean it between each slice.
Whether you’re looking to showcase winter citrus at its peak or simply want to add some sunshine to a gray day, these Ruby Red Grapefruit Bars deliver pure happiness in every bite.
