1. Grind macadamia nuts with the two tablespoons flour in a food processor until it is a coarse flour. Set aside. ( Don't over mix this or else you will have macadamia nut butter and will have to start all over)

2. Combine the rest of the flour with cornstarch and salt and set aside. 

3. Cream sugar and butter in a bowl of a stand mixer with paddle attachment until light and fluffy, 2-3 minutes.  Add lemon zest, vanilla, and egg yolks. Mix again, scraping down sides of bowl when needed.  

4. Add in flour mixture then macadamia nut flour, mix on low until just combined. 

5. Using your hands shape the dough into a ball then divide dough in half. Press into discs, wrap in plastic wrap.  Chill for 4 hours up to two days

6. When ready to bake heat oven to 325 Deg F. Prepare baking sheets with parchment paper. 

7. Roll out dough between parchment paper and or wax paper sheets. Lightly dust bottom paper and top of dough with flour if necessary to keep from sticking.  Cut out circles using a linzer cutter or a 2 inch round cutter and a smaller round cutter for the top cookie. Cut one solid cookie and one with a hole in the middle for every pair of cookies. Place cut out cookies on baking sheet two inches apart. Chill for another 20 min. Bake for 9 minutes until cookies are barely golden and centers are set. 

8. Let cookies cool for 5 minutes on the cookie sheet then transfer to cooling rack, cool completely. 

9. Dust the tops of the cookies ( the ones with a hole in the middle) generously with powdered sugar.

10. Spread a thin layer of jam on bottom half with a little more jam in the middle (about two teaspoons), gently press top of cookie onto the bottom, add more jam in the hole in the middle if needed. Chill until cookies are set. Keep in a resealable bag or airtight container with sheets of parchment between layers of cookies, in the fridge or freezer until ready to serve. 

11. Store in fridge or freezer to keep cookies firm.