Preheat the oven to 325°F and line a baking sheet with parchment paper.
In a medium bowl, combine almond flour, arrowroot flour, and salt.
Add the egg, maple syrup, butter, and vanilla extract and stir until well-combined.
Rub a little oil on your hands to prevent the cookie dough from sticking, then scoop out one tablespoon of dough and roll it into a ball.
Place the ball on the baking sheet and use the palm of your hand to flatten it a little. Repeat until all the dough has been used.
Press your thumb in the center of each cookie dough ball to make an indention. I usually press my thumb twice to make the shape of an "x." It doesn't actually form an x but it creates a deeper, wider well to hold the jam.
Scoop ½ level teaspoon of jam out of the container and place it in the indention. You should have a little jam left over when you're done. Sometimes the jam can settle a little as the cookies bake, so I keep a little extra on hand to top them off if needed.
Slide cookies in the preheated oven and bake for 14 minutes.
Remove from the oven and add additional jam to any cookies that need more if desired. Allow to cool before serving.