This particular version of the recipe is from http://hugsandcookiesxoxo.com/ (although I have added the gram weights) if you haven't already taken a look at their website I encourage you to do so because they have the most amazing recipes.
4 eggs (whites separated from yolks), room temp
1 teaspoon vanilla extract
3/4 cup (150g) sugar
1 stick (120g) butter, melted
3/4 cup (100g) plain/all purpose flour
2 cups (500ml) milk lukewarm
Icing/powdered sugar for dusting cake
Preheat oven to 325 F degrees.
Grease and Line 8 inch x 8 inch baking dish with parchment.
Separate eggs and add the egg whites to a mixer and beat egg whites stiff.
Place egg whites in a bowl and set aside.
Beat the egg yolks & sugar until light. Add butter and vanilla. Beat for two mins.
Add the flour and mix it in until fully incorporated.
Slowly start adding the milk and beat until everything is well mixed together. Add the egg whites, a third at a time and gently fold them in using a spatula, repeat until all egg whites are folded in.
Pour batter into baking dish and bake for approx 60 minutes or until the top is lightly golden.
Cool and dust heavily with powdered sugar.