Spoon 2 tablespoon (30ml) dollops of thick lemon curd onto a parchment-lined plate. Freeze for at least 1 hour until completely solid.
Preheat oven to 400°F (200°C). Coat four 6-ounce (175ml) ramekins with softened butter and dust the insides with a pinch of granulated sugar.
Whisk melted unsalted butter and granulated sugar until pale. Add whole eggs and yolks one at a time. Stir in fresh lemon juice and zest.
Gently fold in all-purpose flour, baking powder, and kosher salt until just combined. Do not overmix.
Divide half the batter into the ramekins. Press one frozen lemon curd disc into the center of each, then cover with the remaining batter.
Bake for 13 to 15 minutes until the edges are golden but the center still has a slight jiggle.
Rest for 2 minutes. Invert onto a plate, dust with powdered sugar, and garnish with a fresh mint leaf and a twist of lemon zest.
