In a large bowl, simply whisk together the almond flour, einkorn flour, baking powder, and sea salt. Set this aside.
In a separate large bowl, use a hand mixer to beat the softened butter and Besti sweetener until it's light and fluffy. Then, blend in the sour cream and vanilla extract.
Gradually add the dry flour mixture to the butter mixture, beating until a smooth, slightly sticky dough forms. Be careful not to overmix!
Cover the bowl with plastic wrap and chill the dough in the refrigerator for at least 2 hours. This makes it much easier to handle.
While the dough chills, prepare your delicious filling! In a medium bowl, combine the chopped walnuts, raisins, dried cranberries, and Besti sweetener. Pour in the melted butter and stir until everything is evenly coated.
Once the dough is nicely chilled, preheat your oven to 350°F (177°C). Line a baking sheet with parchment paper for easy cleanup.
Using a medium cookie scoop (about 1.5 to 2 teaspoons of dough per cookie), drop dough balls onto the lined baking sheet, spacing them about 2 inches apart. Gently flatten each dough ball and use your thumb to create a large well in the center. Don't worry if the edges crack a little; just gently pinch them back together.
Spoon a generous amount of the prepared filling into each well, pressing it down gently so it stays in place.
Bake for 12-15 minutes, or until the edges are beautifully golden brown. Let the cookies cool completely on the baking sheet to allow them to firm up perfectly before enjoying!