1

Preheat the oven to 375°F. Line a 13 by 17-inch sheet pan with parchment paper. In a bowl, whisk together the flour and baking powder and sift them.

2

In a second bowl, combine the eggs and granulated sugar and beat on high speed with a stand mixer fitted with the whisk attachment for about 3 minutes or with a handheld mixer for 10 minutes, or until pale and almost tripled in volume. Stir in the cream and zest.

3

Whisk the butter into the egg mixture. Gently stir the dry ingredients into the egg mixture with a whisk, just long enough to eliminate lumps.

4

Spread the batter in the prepared sheet pan with an offset spatula. Bake for about 15 minutes, or until firm to the touch.

5

Take a sheet of parchment paper the same size as the sheet pan and sprinkle it with confectioners’ sugar. Remove the cake from the oven and quickly flip it out over the parchment paper. Immediately peel away the cooked parchment paper from the bottom of the cake. Sprinkle the top of the cake-what was the bottom-with confectioners’ sugar.