Rhubarb Crumb Cake

I was finally able to buy some rhubarb! Woohoo! Naturally I didn't know how much I needed so I bought a bunch -- I see a lot of rhubarb baked goods for this week. First up is the Big Crumb Coffee Cake that I saw on Smitten Kitchen several weeks ago. As far as coffee cakes go, not the quickest and easiest to throw together because you have to slice the rhubarb and toss with some stuff, mix the sour cream and eggs, mix the crumb mixture up and mix up the flour and dry ingredients. I used a lot of bowls and measuring utensils to make this happen -- but that's okay because it was worth it.

This cake is half crumb and half cake with sweet/tart rhubarb contrasting with the gingery/cinnamony spicy cake. mmmm.... well worth the wait, and well worth the rhubarb. Smitten mentions that you can use raspberries or blueberries instead of rhubarb and I'm sure you could, but I love the tart contrast of the rhubarb. Besides, blueberry crumb cakes are a dime a dozen, but rhubarb crumb cakes... not so common.

I found the recipe on Smitten Kitchen, but it's a Melissa Clark recipe that ran in the New York Times. Not sure if it makes that much difference, but want to get the sourcing right and give credit where credit is due. My pictures aren't quite as pretty as I want them to be but we're expecting Chris' sister to arrive any minute and I wanted to get the blog done before she got here. :)

For the rhubarb filling:

1/2 pound rhubarb, trimmed
1/4 cup sugar
2 teaspoons cornstarch
1/2 teaspoon ground ginger

For the crumbs:
1/3 cup dark brown sugar
1/3 cup granulated sugar
1 teaspoon ground cinnamon
1/2 teaspoon ground ginger
1/8 teaspoon salt
1/2 cup melted butter
1 3/4 cups cake flour (I was out and used all-purpose and it worked great)

For the cake:
1/3 cup sour cream
1 large egg
1 large egg yolk
2 teaspoons vanilla extract
1 cup cake flour (ditto on the all-purpose flour–worked just fine)
1/2 cup sugar
1/2 teaspoon baking soda
1/2 teaspoon baking powder
1/4 teaspoon salt
6 tablespoons softened butter, cut into 8 pieces.

Preheat oven to 325 degrees. Grease an 8-inch-square baking pan. For filling, slice rhubarb 1/2 inch thick and toss with sugar, cornstarch and ginger. Set aside.

To make crumbs, in a large bowl, whisk together sugars, spices, salt and butter until smooth. Stir in flour with a spatula. It will look like a solid dough.

To prepare cake, in a small bowl, stir together the sour cream, egg, egg yolk and vanilla. Using a mixer fitted with paddle attachment, mix together flour, sugar, baking soda, baking powder and salt. Add butter and a spoonful of sour cream mixture and mix on medium speed until flour is moistened. Increase speed and beat for 30 seconds. Add remaining sour cream mixture in two batches, beating for 20 seconds after each addition, and scraping down the sides of bowl with a spatula. Scoop out about 1/2 cup batter and set aside.

Scrape remaining batter into prepared pan. Spoon rhubarb over batter. Dollop set-aside batter over rhubarb; it does not have to be even.

Using your fingers, break topping mixture into big crumbs, about 1/2 inch to 3/4 inch in size. They do not have to be uniform, but make sure most are around that size. Sprinkle over cake. Bake cake until a toothpick inserted into center comes out clean of batter (it might be moist from rhubarb), 45 to 55 minutes. Cool completely before serving.