Preheat your oven to 350°F.
Lightly oil an 8×8 baking dish with coconut oil and then line it with parchment paper. (The oil helps hold the parchment paper in place.)
Use a lemon zester to remove the zest from one of your lemons, then cut the lemon into quarters and squeeze the juice into a small bowl. Continue this process with as many lemons as needed to get ⅔ cups of juice.
Crack 6 whole eggs and 3 egg yolks into a medium bowl and whisk them together.
Measure out ¾ cup of honey and set it aside for the lemon filling. In just a minute you’re going to make the crust and pop it in the oven to bake a little before adding the filling. Once the crust is pre-baked it’s important to immediately (but gently) pour in the filling and place the bars back in the oven. If the crust cools before the filling is poured in it floats to the top, so you’ll want to be able to mix everything together quickly.
Now that I’ve explained that, let’s make the crust! Place all your crust ingredients except the egg in a food processor and pulse until combined. Add the egg and pulse again until the dough starts to ball up. Easy peasy.
Use a spoon to scoop the slightly sticky dough into your baking pan. Lightly oil your hands, then use your fingertips and palms to press the dough evenly into the bottom of the baking dish. Bake for 8 minutes.
While the crust is baking, it’s time to make the filling. Add the lemon juice, 1 tablespoon of lemon zest, ¼ teaspoon vanilla and ¾ cup honey to the bowl with with the eggs. Whisk everything together until it’s well combined.
Mix some hot (but not boiling) water with the arrowroot together until it forms a slurry, then whisk the slurry into the filling ingredients. The water should be hot but not near boiling, because that will cause the arrowroot to become gummy.
When the crust is ready, remove it from the oven and set the pan on a hot pad or trivet.
Pour the lemon custard filling into the pan with the pre-baked crust, then immediately return the pan to the oven and bake the lemon bars for 25-30 minutes or until set in the center. When it’s ready, it should feel slightly jiggly in the center but not liquid. Allow the lemon squares to cool for at least 2 hours before serving.
Serve at room temperature or chilled. Personally, I prefer them at room temperature because it highlights their custardy creaminess, so I store mine in the fridge but let them sit out at room temperature for at least 30 minutes to an hour before serving.
Although I rarely use refined sugar in my house, I do sometimes dust these with organic powdered sugar if it’s a special occasion and I want them to be extra pretty. If you plan to dust yours, just keep in mind that they have to be dusted just before serving or the powdered sugar will dissolve into the custard.