Grind macadamia nuts in food processor until they reach the texture of coarse sand. Set aside.
In the bowl of a stand mixer (or mixing bowl with electric beater), cream butter, sugar, and salt until fluffy and pale in color.
Add egg yolks and beat until homogenous.
Add flour and ground macadamia nuts. Mix until well incorporated.
Wrap the dough in plastic wrap and place in fridge to chill for at least half an hour but up to overnight. I pat my dough into a flat disc shape before chilling to make rolling out the dough easier after it's cold. If making Big Island Candies style rectangle cookies, shape dough into a rectangular log instead.
When ready to bake, prepare a baking sheet with parchment paper.
Roll out the dough to approximately 1/4 inch thick for pineapple cookies. For rectangle cookies, slice the log into 1/4 inch thick rectangles.
Use a pineapple cookie cutter (or other shape of choice) to cut out cookies and arrange on your baking sheet. While these cookies are not supposed to spread, I like to leave an inch of space in between just in case.
Preheat your oven to 350F. While oven is preheating, I recommend putting your cookies back into the fridge or freeze to chill again, in case slicing them warmed the dough up too much. Chilled dough is less likely to spread.
Bake for 15-20 minutes or until the edges begin to brown. Watch carefully as baking time will differ depending on the oven and type of baking sheet used.
Allow cookies to cool to room temperature. If dipping in chocolate, heat chocolate and coconut oil in microwave at 30 second increments, stirring in between until chocolate is smooth. For a half batch of chocolate dip, I used 1/2 cup chocolate chips and 1 tsp of coconut oil. For white chocolate, I found that 1/2 cup of chocolate chips needed 2 tsp of oil to be thinned out.
Dip pineapple cookies in chocolate dip, using a spoon to cover all desired areas and scrape off excess chocolate. Place bake on baking sheet to set.
When chocolate has hardened, eat and enjoy! Leftovers can be kept in an airtight container at room temperature. If you find that your chocolate is not hardening enough at room temperature, you can also store the cookies in the fridge in an airtight container.