Start by making the lemon curd. Add sugar and lemon zest to a food processor or high-speed blender. Blend until combined (it will smell super citrusy!).

Cream the room temperature butter. Add the sugar and then add the eggs in one at a time mixing between each addition. Lastly add the lemon juice and salt and mix together until just combined. 

Transfer the lemon mixture to 2-quart saucepan and cook over low heat until thickened, stirring constantly. When you have your first bubble and the mixture is a lot thicker than what you started with, you'll know it's done.

Set aside to let cool.

In medium bowl combine egg, peanut butter, maple syrup, vanilla extract, almond flour, baking soda, cinnamon and salt. Mix until well combined.

Refrigerate for 10 minutes and preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.

Use a cookie scoop to portion out the dough. Roll it into balls and gently flatten it out with your palm just a little. 

Bake for 10-12 minutes until the cookies are set.

Remove from oven and use the back of a 1/2 tbsp. to make "thumbprints" in the middle of each cookie. Once the cookies are cooled spoon a little lemon curd on top of each one. 

Store leftover lemon curd and cookies in the fridge for up to a week.