Add the softened light butter, Truvia Sweet Complete Confectioners, and egg white to a mixing bowl. Beat with a mixer until smooth and creamy.

Add half of the oat flour and mix on low speed. Transfer the dough to a board and add the remaining flour in small batches until a soft dough forms.

Roll the dough between two sheets of parchment to a 1/4-inch thickness. Cut out two rectangles measuring about 3.5 x 7 inches each.

Place both rectangles on a parchment-lined baking tray. Use a piping nozzle or small cutter to punch out small “windows” in one of the rectangles.

Chill both pieces in the refrigerator for 1 hour.

Bake at 350°F for 10–14 minutes or until the edges are lightly browned. Cool completely on a wire rack.

Spread the raspberry jam over the solid rectangle. Place the cut-out rectangle on top. Add a small amount of jam into each window if desired and dust lightly with additional Truvia confectioners.

Melt the Lily’s chocolate and use it to pipe reindeer antlers or decorative lines on top. Use small drops of chocolate to attach the candy eyes. Add sugar-free sprinkles while the chocolate is still soft.

Refrigerate the cookie for 1 hour to set, then slice into portions and serve.