Preheat your oven to 350°F (175°C). This is crucial for ensuring your cookies bake evenly.
Line a baking sheet with parchment paper. This will prevent your cookies from sticking and make for easy cleanup.
In a large mixing bowl, combine the almond flour, rolled oats, all-purpose flour, and salt. Stir until well mixed.
In another bowl, cream together the softened butter, vegetable shortening, and brown sugar. Beat until light and fluffy, about 2-3 minutes.
Add the egg yolk and vanilla extract to the butter and sugar mixture. Mix until fully incorporated.
Gradually add the dry ingredients to the wet ingredients. Mix until a dough forms. Be careful not to overmix!
Using a cookie scoop, portion the dough into small balls and place them on the prepared baking sheet, leaving about 2 inches of space between each cookie.
Using your thumb (or the back of a spoon), press a small indentation into the center of each cookie ball.
Spoon 1/2 teaspoon of forest berries jam into each thumbprint. Don’t be shy; this is the best part!
Bake the cookies in the preheated oven for 12-15 minutes, or until the edges are lightly golden.
Once baked, remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.
