Preheat the oven to 340°F (170°C). Line a 8-inch (20 cm) square pan with parchment paper.
Separate the eggs into yolks and whites.
In a bowl, whisk together egg yolks, honey, lemon zest and vanilla until smooth.
Add Greek yogurt.
Whisk to combine.
Stir in shredded coconut, baking powder and salt.
Whisk to combine.
In a clean bowl, beat the egg whites until soft peaks form.
Fold the egg whites into the batter in 2–3 additions.
Mix gently to keep the batter airy.
Pour the batter into the prepared pan.
Drop small teaspoons of lemon curd over the surface.
Lightly swirl with a knife (do not overmix).
Bake for 55–60 minutes, until the cake is set and lightly golden. If it starts browning too quickly, loosely cover it with aluminum foil.
Let cool completely before slicing. Dust with unrefined powdered sugar if desired and cut into bars. Enjoy!