Pre heat oven to 180°C / 350°F / Gas Mark 4.
Put the dry ingredients (flour, baking powder, salt, sugar and cinnamon) in a mixing bowl.
Mix the linseed / flaxseed egg, oil and vanilla together in a separate bowl. Then add to the dry ingredients.
Add the macadamia nuts. You should have a dough mixture with all ingredients combined.
Sprinkle some flour on a firm flat surface. Roll out the dough to a thickness of around 4mm. Use a cookie cutter of the shape of your choice to cut the dough. It may be easier to divide the dough into 3 or 4 pieces and roll each separately (there's a lot of dough once all rolled out!).
Place the cut out dough on baking trays covered with a piece of baking parchment (this ensures they don’t stick to the bottom).
Bake in the oven for 15-20 mins. The trays may need to be turned around half way through the cooking time. If the trays are on different levels of the oven, those at the top may cook quicker, and those on the bottom may need an extra few minutes.
When the cookies are ready, they should be only very slightly browned. They may still have a slight softness to them, but they will harden once cool. Place on a cooling rack once out of the oven.
To decorate, melt the white chocolate in a bowl over boiling water. Use a spoon to drizzle the chocolate over the cookies. Wait for them to cool, then enjoy.