1-Prepare the crust: Preheat oven to 350°F. Pulse 1½ cups macadamia nuts into fine crumbs, add 6 tbsp melted butter and 3 tbsp Swerve confectioners, press into parchment-lined 8×8 pan, bake 20-25 min until golden, then cool completely.

2-Make the lemon filling: Whisk 4 eggs, 4 yolks, and ½ cup Swerve confectioners. In a saucepan, boil ½ cup lemon juice, 1 tbsp zest, 1 tsp xanthan gum, ¼ cup Swerve confectioners, and ¼ tsp salt for 1 minute, whisking constantly.

3-Temper eggs and cook custard: Off heat, slowly whisk hot lemon mixture into eggs, then return to saucepan. Cook on medium-low, whisking 5 min until thick and spoon-coating. Remove from heat, whisk in 2 tbsp butter until glossy, cool 10 min.

4-Blend until silky smooth: Process the slightly cooled filling in a food processor 2-3 min until pale and fluffy. Optionally add lemon extract or essential oil for extra flavor.

5-Assemble and chill: Spread filling over completely cooled crust, smooth top, cover with plastic wrap, refrigerate at least 4 hours (overnight best). Lift out with parchment, dust with powdered Swerve, and slice into 12 bars.