1-First, zest one or two blood oranges and set the zest aside, then juice them and strain through a fine mesh sieve to get 1 cup of clear juice. Simmer this juice over medium-high heat until it’s reduced to ½ cup, which takes 10 to 15 minutes, and stir in the citric acid until it dissolves. You can prepare this ahead and refrigerate it for later use.

2-Next, set up a double boiler with simmering water and place a heat-proof bowl over it. Whisk the 2 large eggs, 4 large egg yolks, ½ cup (100 g) granulated sugar, and 1 teaspoon blood orange zest in the bowl, then add the reduced juice and whisk regularly until the mixture thickens to about 165 degrees F.

3-Preheat your oven to 350 degrees F and prepare an 8×8-inch pan by buttering it and lining with parchment, also buttering the parchment. Melt the ½ cup (113 g or 1 stick) unsalted butter over medium heat, stir in the ¾ cup (150 g) granulated sugar until smooth, and whisk in the 1 tablespoon (14 g) vegetable oil.

4-Add the 1 large egg and 1 large egg yolk, whisking vigorously for one minute, then mix in the 1 teaspoon vanilla extract. Fold in the ⅓ cup (42 g) all-purpose flour, ½ cup (50 g) Dutch process cocoa powder, and ¼ teaspoon fine sea salt until just combined, then pour the batter into the pan and spread evenly.

5-Bake for 15 to 17 minutes until the top is set but still gooey inside. Remove from the oven, spread the orange curd over the brownie layer, and bake for another 5 to 7 minutes until the curd sets. Cool on a wire rack for one hour, then refrigerate for at least one hour or overnight before cutting into 16 squares. For clean cuts, warm and oil the knife blade between slices. If you’re looking for more baking inspiration, explore our chocolate desserts guide for complementary ideas.