Preheat oven to 170C. Beat the butter until pale and creamy. Add the sugar and beat again.
Separate the eggs and put the whites to one side for making the meringue later. Add the yolks to the butter and little at a time and beat well.
Sift together the flour and baking powder and add the the butter and combine well. This is likely to end up looking like large crumbs.
Press the crumb dough into a steep sided baking tin. I use a loose bottomed brownie pan. And bake for 15 minutes. Then remove from the oven and cover the pastry in lemon curd.
Whilst the pastry is cooking make the meringue. Whisk the egg whites until they hold stiff peaks. Turn your whisk / beater to the lowest speed and add the sugar and tablespoon at a time, ensuring the sugar is fully mixed in be fore you add the next amount.
When all the sugar has been added to the whites, continue beating on a low speed until the meringue is glossy and holds soft peaks. Spoon the meringue on top of the lemon curd and return the brownie pan to the oven. Bake for approximately 30 minutes until the meringue is crisp on top.
Remove from oven and place pan on wire rack to cool fully before using a palette knife to remove from pan. Cut into approx 16 slices and serve