01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the almond flour, sugar, salt, and baking soda until evenly distributed.
03 - In a separate bowl, beat the egg, then whisk in the melted butter, lemon zest, lemon juice, and vanilla extract until smooth and well combined.
04 - Pour the wet mixture into the dry ingredients and stir with a spatula until a soft, cohesive dough forms.
05 - Scoop tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart. Flatten each mound gently with your fingers or the back of a spoon.
06 - Sprinkle sliced almonds over each cookie and gently press them into the surface so they adhere during baking.
07 - Bake for 12 to 15 minutes, rotating the sheets halfway through, until the edges are golden brown and the centers are set.
08 - Let the cookies rest on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely before serving or storing.