Preheat oven to 340°F (170°C). Line a 9-inch square baking pan with parchment and grease with butter.
Sift the two flours into a medium bowl and mix with salt and baking powder.
Using a stand electric mixer, beat eggs, powdered sweetener, and vanilla for 5 to 8 minutes until creamy, thick and triple in size.
While mixing slowly, pour in cooled melted butter and mix gently but thoroughly. Slowly whisk in greek yogurt and sifted dry flour mixture, interchangeably, in 3 to 4 additions, stirring carefully each time.
Bake for 25 minutes or until the edges pull away slightly from the pan. Use a toothpick to check for doneness.
Allow cooling on a baking rack. Put in a freezer for 30 to 60 minutes. Freezing before cutting and coating is very important, otherwise, the bars might fall apart. Cut into 36 squares.
Coating
Place pieces of chocolate, cacao powder, and butter into a heatproof bowl.
Bring milk to boil and pour over the chocolate. Wait for 5 minutes for the chocolate to melt and stir thoroughly to get uniform chocolate cream.
Put shredded coconut in a separate bowl. Helping yourself with a pair of forks, dip each bar/square into the chocolate coating, let drain for a couple of seconds, and roll in shredded coconut. Place each coconut bar on a cooling tray to set.
Store in an airtight container and refrigerate for up to 5 days.
Notes
1.3 net carbs per serving.Dip each bar/square in the chocolate coating quickly, otherwise they might start falling apart.Bring the keto coconut bars (keto Lamingtons) to room temperature before serving.