Sift potato starch and baking powder. Set aside.

Cream butter and 1 cup sugar until well incorporated, about doubled in size, and it turns whiter.

Add yolks one at a time; scrape down sides.

Add lemon zest and juice and mix until incorporated.

In a separate bowl, whip the egg whites until frothy.

Add ¼ cup sugar to the egg whites a little at a time and whip until stiff peaks form.

Fold the dry ingredients into the egg yolk/butter mixture. Fold in half the egg whites and incorporate well.

Fold in the remaining egg whites and mix gently until well combined.

Butter the ramekin and lightly dust with a bit of sugar.

Spoon the batter into the ramekins until they are half filled.

Place in a cold oven. Turn temperature to 350F degrees.

Bake for 15-20 minutes until cakes are beginning to brown slightly.

Cool for 5 minutes. Remove from ramekins and serve with fresh berries and whipped cream or eat without toppings if you prefer.