Preheat and prep the pan: Set your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment, leaving a slight overhang for easy lifting. Lightly grease the sides.

Mix the crust: In a bowl, combine 2 cups almond flour, 1/3 cup granulated low carb sweetener, and a pinch (1/4 tsp) sea salt. Stir in 1/2 cup melted unsalted butter and 1/2 teaspoon vanilla extract until the dough is evenly moistened and clumps together.

Press and par-bake: Press the crust mixture firmly into the lined pan, creating an even layer. Dock with a fork a few times. Bake for 12–14 minutes until lightly golden at the edges. Set aside to cool slightly.

Whisk the filling: In a clean bowl, whisk together 3 large eggs, 2/3 cup granulated low carb sweetener, 1/2 cup fresh lemon juice (about 3–4 lemons), 1 tablespoon lemon zest, and a pinch of salt. For extra body, whisk in 1 tablespoon coconut flour. The batter should be smooth and pourable.

Pour and bake: Pour the filling over the warm crust. Reduce oven temperature to 325°F (165°C). Bake for 18–22 minutes, or until the center is just set with a slight jiggle when you nudge the pan.

Cool completely: Let the bars cool in the pan on a rack until room temperature. Then chill for at least 2 hours. This step firms the custard and makes slicing clean and easy.

Dust and slice: Lift the bars out using the parchment. Dust with powdered low carb sweetener if you like. Slice into 16 squares with a sharp knife, wiping the blade between cuts for tidy edges.

Serve: Enjoy chilled or at cool room temperature. Expect a bright, lemony bite with a tender, buttery crust.