Preheat the oven to 325°F.
Prepare the crust by adding all of the ingredients into a medium bowl and working them together using a rubber spatula or wooden spoon. Once combined, transfer the crust to a non-stick 9-inch tart pan, flattening and spreading to the edges.
Place the tart pan on top of a baking sheet, in case oil leaks. Bake until golden brown, about 25 minutes.
In the meantime, peel 2 lemons and remove large seeds, then transfer to a high-speed blender (do not worry if there are remaining small seeds). Blend for 20 seconds.
Into a medium bowl, add lemon purée, zest, and juice of the 2 remaining lemons (there should be 6 tablespoons of juice, use an extra lemon if necessary), whole eggs, egg yolks, coconut sugar, and coconut flour, and whisk until smooth.
When the crust is ready, remove from the oven and let it cool for at least 20 minutes. Then, carefully pour the filling over the crust and bake until the filling is set, about 25 minutes.
Remove from the oven and allow to cool completely on a cooling rack. Dust with powdered monk fruit and serve. Store in the fridge for up to 5 days.
