In a large bowl, use a stand or hand mixer and cream the butter, oil, sugar and amaretto until fluffy. Fold in egg yolks and lemon zest until incorporated, but don’t over mix.
Sift in flour, almond meal, cinnamon and salt into the butter mixture. Switch to a spatula and mix the batter until a dough forms. Divide the dough into quarters (into 4), and wrap them individually with seran wrap. Refrigerate for 2 hours or overnight.
Preheat the oven to 350°F and line two baking sheets with parchment paper. Remove one piece of dough from the refrigerator at a time. Place the dough between two sheets of parchment paper and roll it out to ¼ inch thickness. Use a 3-inch cookie cutter or the rim of a drinking glass to cut out the cookies.
Place the cookie rounds on the lined baking sheet. Cut out a top for each cookie, using a smaller cookie cutter or even the base of an icing tip to cut out the center so the blackberry jam will be exposed. Repeat with the remaining pieces of dough. If the dough gets too soft, place it in the freezer for about 5 minutes to firm up again. A firm dough ensures that the cookie rounds hold up well.
Bake the cookies for 12 minutes, then transfer to a cooling rack until cooled. Once cooled, spread the bottom half of each cookie with the blackberry jam, leaving a thin border around each cookie. The jam ensures that the cookies stick together. Place the top of each cookie with the middle cut out on its corresponding bottom half. Return to the cooling rack so that the cookies seal completely.
Notes
These cookies preserve at room temperature for 2 days. Store them in an airtight container. The texture of these cookies are meant to be crumbly and similar to shortbread cookies.
Recipe by My Digital Kitchen at https://www.mydigitalkitchen.ca/2020/12/16/linzer-cookies/