In the bowl of a stand mixer, fitted with the paddle attachment (or a large bowl if using a handheld mixer) combine the almond flour, oat flour, arrowroot powder, coconut sugar and salt and mix until combined.
Add in the eggs and coconut oil and continue mixing until thoroughly combined. The dough should be a little sticky, but not too sticky that it sticks to your finger when touched. If its too dry, add a touch more coconut oil, it its too wet, add a little more oat flour.
Wrap the dough in plastic wrap and chill in the refrigerator for at least 2 hours or, if making ahead, up to 2 days.
Once the dough has rested and chilled, preheat your oven to 325° F and line a baking sheet with parchment paper or a silpat.
Roll portions of the dough into golf-sized balls using your hands; place them on the cookie sheet and gently press down on them to flatten slightly. This step is easier if you keep your hands a little wet with water, to prevent the dough from sticking to your hands.
Next, use your thumb to press into the middle of each cookie to create a bit of a "well". Fill each well with your jam of choice, using no more than about 2 teaspoons per cookie to prevent them from bubbling over.
Bake in pre-heated oven for 10-13 minuted until the cookie is baked and the edges are slightly turning golden brown. Transfer to a wire-rack to cool a top with shredded coconut, if using.