Sift the flour, spices, salt and the baking powder together. Mix well and sift again. Set aside.
Pulse the nuts in a food processor or blender till they turn to a coarse powder. Set a side.
In a large mixing bowl beat the butter until fluffy . Add the brown sugar and beat till the mix is creamy. Add the egg yolks and vanilla and beat in until evenly blended.
Add the flour to the butter mix in batches and stir in. You may have to mix using the spatula after the fist half of the flour is mixed in. Add the nuts to the last couple of tablespoons of flour and transfer everything to the butter mixture. Mix evenly, but do not overwork the dough.
Divide the dough in half. Form into balls , and pat into discs about 4 inches in diameter. Cover with plastic wrap and refrigerate for at least 1 hr, preferably overnight.
Lightly flour a work surface and roll the dough out into 1/8 inch thickness. Using cookie cutters cut out into desired shapes. From half the cookies cut out center portions. Gather the leftover pieces of dough and re roll and repeat the process.
Pre-heat the oven to 350°F. Arrange the cookies on a cookie sheet leaving at least an inch space between them. Bake cookies for about 9 to 11 minutes. The cooking times vary depending on thickness. The cookies are done when the bottoms brown and edges are firm. Remove the trey from oven. Cool in the tray for 2 minutes and using a spatula transfer the cookies to a cooling rack to cool completely. Store in airtight containers.
Sift confectioner's sugar over the cookies with the center cut outs . Spread a little jam on the bottom of a cookie without the cutout and place the cutout cookie on top with the powdered sugar side facing away from the jam.
For detailed instructions go to https://oventales.com/linzer-cookies/ .