Cream butter until fluffy (I usually do this in mixer but the food processor works too). Add eggs, sugar, vanilla extract, almond extract, baking powder, salt if using. Scrape down and mix again.

Add flours and mix, scraping down the bowl once mid mix.

Shape into small balls (¾ inch diameter)

Optional: dip in bowl of egg mixture then roll in nut mixture and set on parchment lined baking sheet.

Make the "thumbprint" with pinky or some similarly sized implement (I use the end of a mini spatula dipped in starch) to create the imprint . If the imprints have puffed up push them (gently) back down.

Bake until light golden brown and set (about 10 -15 minutest total).

Remove and let cool a bit on the pan.

While cooling melt jam in microwave or on stove and blend with hand blender if it is lumpy jam like strawberry with whole strawberries in it. Fill each cookie – I use a little demitasse spoon to keep it precise you could use a pastry bag if you are so inclined.