• Preheat the oven to 325°F. Prepare an 8” x 8” pan by lightly greasing and flouring it.

Shortbread crust:

• Add the sugars and flour to a large bowl and whisk together to combine.
• Add the butter by cutting it in with two knives, or pulse in a food processor. You can also use your fingers to work it in. The mixture should be crumbly in texture, with pea-sized clumps.
• Stir in the egg yolks with a large spoon until just combined.
• Press the dough into the prepared pan, and bake for about 30 minutes. The edges should just be turning golden.
• When the crust is done its first turn baking, remove it from the oven, lowering the temperature to 300°F.

Pummelo filling:

• Make the filling as the crust bakes.
• Add the egg yolks and the sugar to a medium saucepan – do not turn on the heat just yet.
• Stir as you add the pummelo juice and butter.
• Now, turn to a medium setting, and cook the mixture as you stir it constantly for about 8 minutes. The curd should thicken enough to coat the back of a spoon as you draw it out – don’t allow it to come to a full boil.
• Remove from the heat, and stir in the pummelo zest quickly.
• Pour the pummelo curd over the baked crust, using a spatula to spread it evenly.
• Return the pan to the oven, and bake for another 16 to 18 minutes. The curd filling should still be a little wiggly.
• Remove from the oven, and allow the bars to cool in the pan for about one hour.
• Dust with the powdered sugar, and cut into bars.
• You can store them up to 3 days in an airtight container at room temperature.