One of the best indicators that spring is finally here to stay is when my rhubarb plant finally pops above the ground. It is incredibly faithful; no matter how cold the winter was, it never fails to grow again each May. Right now it is out-of-control, as the towering green leaves threaten to take over my entire garden. I’ve been looking for new ways to cook and bake with it, and was intrigued by several rhubarb upside-down cakes I spotted on Pinterest. However, I had a bucket of brioche in my fridge, so instead of mixing up cake batter I simply rolled out my dough and placed it over hot rhubarb and sugar. It was a success: a sweet-tart treat perfect for breakfast, or afternoon snacking.
1 1/2 pound brioche dough (page 300 of The New Artisan Bread in Five Minutes a Day) or whole wheat brioche dough
5 tablespoons butter
1 cup sugar
1 teaspoon lemon juice
1 teaspoon vanilla
a good pinch of salt
(about) 1 pound rhubarb, cut into long pieces, or 1-inch pieces (see below picture for details)
Preheat your oven to 375.
Size your rhubarb: If using longer pieces of rhubarb to cover the top of the cake, you may want to piece them to fit the pan (instead of using a specific weight measurement) as shown in the picture above. I used about 6 stalks of rhubarb for this cake. If you’d prefer to use small pieces scattered over the top, use a pound of rhubarb, and cut the stalks into 1-inch pieces.
Melt the butter and sugar together in a 9-10 inch cast iron pan. Add the lemon juice, vanilla, and pinch of salt, and stir to combine. Carefully layer the rhubarb over the melted sugar mixture, and let cook until the rhubarb is tender, about 5-7 minutes.
While the rhubarb is cooking, flatten the dough with your hands or a rolling pin, and roll out the brioche into a 9-10 inch circle (you want it to snuggly fit the pan you are using).
When the rhubarb is tender, very carefully (the pan is hot!) place the circle of brioche over the top of the cooked rhubarb. Make sure the dough is touching the sides of the pan. Place in the oven and cook for 25-35 minutes, until the brioche is golden brown.
Move the pan to a wire rack, and let the cake sit for 10 minutes. After ten minutes, carefully flip the cake onto a serving platter.
Let the cake cool slightly, and then serve. This cake is best eaten the day it is made.