Preheat the oven to 350 F.Line an 8X8 square pan with parchment paper, making sure to leave parchment overhang on both sides of the pan so you can lift the bars later!
In a small bowl combine flour, baking powder, and salt, set aside
In a separate large bowl, use a hand mixer to cream the butter and sugar. This should take about 3 minutes. Scrape down the sides of the bowl half way through and continue to mix until light and fluffy. Scrape the sides of the bowl with a nonstick spatula again
Add in egg and mix again until combined
Scrape down the sides of the bowl with a nonstick spatula and the dry ingredients you set aside ( flour, baking powder and salt). Mix until thick dough forms
Scoop batter into the prepared pan and smooth top with an offset spatula.
Using a spoon, dollop lemon curd and fluff on top of smoothed dough. Using a knife, swirl the the top of the bars.
Bake for 15-20 minutes or until the edges are golden brown. If baked too long, the fluff will burn so make sure to check at 15 minutes.
Let cool for 20 minutes. Then cut and serve!