Place the flour, oats, sugars, baking powder and salt in the bowl of a stand mixer.Add the butter in and mix with the paddle attachment on medium speed until tiny pebbles form. Add the extract and the yolk and mix until the dough comes together.
Heat oven to 350F and line two cookie sheets with parchment paper. Set aside ¼ of your dough for crumbling later. Scoop the remaining dough with 2 Tbsp or a ¾oz portion scooper onto the cookie sheets. Dent the centers of each cookie with your thumb, adding a little water to your finger if it feels sticky. Fill eachcenter with jam. Crumble the remaining cookie dough around the edges and bake for 15-20 minutes, or until the edges are a lovely light golden brown color.