It was my birthday today! Well, technically yesterday, but you know what I mean.
I brought to the (sadly, so sadly) final quizbowl practice of the summer this rhubarb lemon brioche cake that I've had planned for some time, adapted from a combination of some sketchy Hungarian fruit cake recipe and a plum brioche cake recipe that was a little oddly worded for my tastes. I thought the cake was "too": too little lemon, too little rhubarb, too much sugar, too much baking. But the rest of the group seemed to like it! So here is my (heavily) altered recipe. There's no paprika, I promise.
Rhubarb lemon brioche cake, adapted mostly from here
150 g butter, softened, plus more for the pan
4 egg yolks
3 egg whites
120 g brown sugar, plus more for tossing with the rhubarb
1/4 tsp salt
juice and zest of 1 lemon
1 tbsp sour cream
Preheat the oven to 350 F. Beat the butter until fluffy, then add the sour cream and brown sugar and beat to combine. Add the egg yolks one at a time. Beat 10 minutes, or until light and fluffy. Stir in the flour. Add the salt to the egg whites and begin to beat them; about halfway to the soft peak stage, add a few drops of lemon juice. Continue to beat until the whites hold soft peaks. Stir a generous spoonful of whites into the batter to lighten it, then gently fold into the batter along with the rest of the lemon juice (reserving a small amount to toss with the rhubarb) and the lemon zest. Spread in a generously buttered pie pan. Toss the rhubarb with sugar and lemon juice and arrange it on top of the batter. Bake for 30 minutes or until just set and still very moist.