Sour-sweet springtime treat

One of the tastes of spring I get very excited about is rhubarb, that crunchy and tart stalk that adds so much vibrancy to desserts. I still fondly recall a spring and summer childhood snack, dipping the end of a cut rhubarb stalk into a cup of sugar and eating it raw like a sugar-tipped celery stalk.

While visiting the Dane County Farmer's Market last weekend on my birthday, I bought a pound and a half of fresh, hot-pink rhubarb stalks to take home. I was dreaming of pie (like the one my grandmother said she made for my grandfather for his birthday, also last weekend), but I recalled that I had a bunch of cake flour left over from Easter and that I had powdered buttermilk in the refrigerator that needed to be used up, so I changed course and went for upside-down cake instead. The cake recipe is mostly taken straight from Mark Bittman's How to Cook Everything (10th Anniversary ed.), but with modifications to accommodate rhubarb, which was not one of the fruit options he gave, and the fact that I don't own a cake pan of the correct size for his original recipe.

Rhubarb upside-down cake
12 pieces

2 sticks unsalted butter, melted
1/4 cup brown sugar mixed with 1/4 cup granulated sugar
1.5 pounds rhubarb stalks, sliced
additional granulated sugar

Preheat oven to 350 degrees Fahrenheit. Pour a few tablespoons of butter into a 9 x 13-inch rectangular cake pan. Keep the rest in a bowl for next part of recipe. Sprinkle the sugar mixture over the butter. Scatter rhubarb slices evenly over the sugar. Sprinkle the rhubarb with about 1/4 cup more granulated sugar.

8 Tbsp powdered buttermilk, reconstituted with water
4 eggs
1 cup granulated sugar
4 cups cake flour
scant 2 tsp baking soda
1/2 tsp salt

Whisk together melted butter, buttermilk, eggs and sugar until mixture lightens in color. Butter may turn to small bits instead of staying liquid. In a separate large mixing bowl, combine dry ingredients. Add the egg mixture and whisk until well-incorporated. Spread the batter over the rhubarb in the cake pan, using a spatula to evenly distribute batter. Bake in the center of oven for 50 minutes or until cake is golden and toothpick inserted into center comes out clean. Cool a few minutes in the pan and serve pieces directly from the pan or invert cake onto a serving platter. Cut into 12 pieces.

Readers may wish to add more sugar to the rhubarb-in-the-pan phase if they like the rhubarb sweeter and with less of its original astringent nature than I do.