Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper.
In a large bowl, whisk together the melted butter and monk fruit sweetener. Add the eggs, lemon juice, lemon zest, and vanilla extract. Whisk until everything is smooth and the zest is evenly distributed.
Add the almond flour, baking powder, and salt. Stir with a spatula until a thick, smooth batter forms. The lemon zest should be visible throughout.
Spread the batter evenly into the prepared pan and smooth the top.
Bake for 22 to 25 minutes, until the top is light golden and a toothpick inserted in the center comes out clean or with just a few moist crumbs. Let the blondies cool completely in the pan.
Once cooled, make the glaze by whisking together the powdered monk fruit sweetener and lemon juice until smooth and pourable. If it is too thick, add a tiny splash more lemon juice.
Drizzle the lemon glaze over the cooled blondies in thin lines. Sprinkle the remaining lemon zest over the top. Let the glaze set for 10 minutes before slicing into 16 squares.