Combine butter, sugars, and cinnamon and use an electric mixer to beat until light and fluffy (at least 30-60 seconds). Stir in vanilla.

In a separate bowl, whisk together all purpose flour, almond flour, cornstarch, and salt. Gradually stir into butter mixture until combined (don’t over-mix, but make sure dough is completely combined).

Form dough into 2 discs and wrap each in plastic wrap. Chill in the refrigerator for at least 30 minutes. While dough is chilling, preheat oven 350F (175C).

Once dough has chilled, work with one disc at a time and transfer to a lightly floured surface. Roll into a ⅛” thick sheet. Cut into 2 ½” circles (I like to use cookie cutters with scalloped edges) and transfer to a parchment paper-lined baking sheet, spacing cookies at least 2” apart. Use a small heart or star shaped cookie cutter (or, if you don’t have one, just use the larger circular end of a piping tip) to cut designs in the center of half of the cookies. Bake the cookies with cutouts on a separate tray from the ones without cutouts to ensure even baking. (I usually take the heart cutouts and just re-roll them with the rest of the cookie scraps to make more cookies)

Bake in 350F (175C) preheated oven for 9-10 minutes or cookies are just beginning to turn light golden brown on the edges. Allow to cool completely before filling.

Once cooled, dust the tops of all of your cookies that have the windows/cutouts. Spoon a heaping teaspoon of jam on the bottom of your remaining cookies and sandwich with one of your top cookies.