Make the white chocolate. Place cocoa butter in a double boiler and heat on medium high until fully melted (or microwave safe bowl and heat on high for one minute, check and heat for 30 seconds until melted). Melting cocoa butter takes longer than traditional fats. Stir in natural sweetener. Stir in vanilla beans (split and strip beans from vanilla bean) or extracts and salt. Place into candy mold and cool in refrigerator until white chocolate is solid, about an hour. Or the speedy method; you can place the molds in a freezer till they are set up, which will only take a couple of minutes versus an hour.
Preheat oven to 375 degrees F (190 degrees C).
Grease baking sheets, or line with parchment paper.
In a large bowl, cream together the butter and sweetener until smooth.
Beat in the eggs one at a time, then stir in the vanilla. Combine the almond flour and baking powder; stir into the creamed mixture until well blended. The dough will be stiff, so mix in the last bit by hand. Mix in the white chocolate pieces and macadamia nuts.
Divide dough into two equal parts. Shape into 9x2x1 inch loaves. Place onto the baking sheet 4 inches apart. Brush with a mixture of water and yolk.
Bake for 20 to 25 minutes in the preheated oven, or until firm. Cool on the baking sheet for 30 minutes.
Using a serrated knife, slice the loaves diagonally into 1-inch slices. Return the slices to the baking sheet, placing them on their sides. Bake for 10 to 15 minutes on each side, or until dry. Cool completely and store in an airtight container.