Preheat oven to 350 F and line a cookie sheet with parchment paper or your favorite non-stick silicone mat. In a large mixing bowl, or in the bowl of a stand mixer with the paddle attachment, cream together butter and white sugar until smooth.
Mix 1/2 tsp of almond extract to the butter mixture. Combine almond flour with butter mixture and mix until well combined.
Form dough into one ball, cover in plastic wrap or place in freezer bag and let chill in refrigerator for 2-4 hours or overnight.
Use a medium cookie scoop or 1 tbsp spoon to scoop out balls of dough onto the lined baking sheet. Poke a hole in the center of each cookie dough ball using the end of a wooden spoon and fill the thumbprint hole with a scant quarter teaspoon of jam.
For best results, let chill in refrigerator for 15 minutes to ensure that the cookies keep their shape as they bake.
Bake cookies 14 to 18 minutes in a preheated oven until golden brown.
Let cool on sheet for a couple of minutes, then remove to wire rack.
Sprinkle with a little bit of confectioners' sugar to serve.