rhubarb and sour cream brunch cake

One of my earliest memories is taking a small bowl of sugar out to the garden to eat rhubarb fresh from the plant. I’d break off a big stalk, dip one end in the sugar and munch away. Crunchy, juicy, and sour-sweet, it was the taste of early summer and everything to come. Just writing this makes me want some.
Not many of us take our rhubarb raw as adults, and though cooked rhubarb keeps none of its crunch, it does keep that pink tartness that makes rhubarb, rhubarb. It’s one of my favorite flavors for sweets because, like citrus, it gives sugar some contrast, balance, and a little sass. This is a go-to coffee cake recipe made super-moist with over a half pound of sour cream, and topped with caramelized nut crunch. With the rhubarb it’s a perfectly balanced little cake. Serve it just as it is, warm from the oven with a big steaming mug of coffee.

For the Cake
½ cup plus 2 tbsp/ 135g unsalted butter at room temperature
¾ cup plus 2 tbsp/ 185g granulated sugar
1 tsp vanilla extract
3 large eggs
1 ¼ cups/ 265g sour cream
2 ¼ cups/ 300g all purpose flour
1 tsp baking powder
½ tsp baking soda
Pinch of salt
2 cups/250g chopped rhubarb plus 2 tbsp granulated sugar

For the Nut Crunch
¾ cup/ 135g brown sugar
¼ cup/ 50g unsalted butter cold and cubed
Heaping ½ cup/ 65g chopped walnuts
1 tsp cinnamon
½ tsp ground cardamom

Make the Cake: Preheat the oven to 350 degrees. Sprinkle the rhubarb with the 2 tbsp sugar and set aside. Sift together the flour, baking powder, baking soda, and salt and set aside. Measure out the sour cream and set aside. In the bowl of a standing mixer or using hand held beaters, cream together the butter and sugar and add the eggs one at a time. Scrape down the bowl. Alternate adding the dry ingredients and the sour cream to the butter mixture, beginning and ending with the dry and mixing well/scraping down the bowl after each addition. Fold in the rhubarb.

Make the Nut Crunch and Assemble: Place all ingredients in a small bowl and crumble together with your hands until well combined. Butter and flour a 9 inch cake pan or ring mold. You may also want to line the pan with parchment paper. Scoop approximately 2/3 of the cake batter into the bottom of the pan and spread half of the nut crunch over the batter. Distributed the remaining batter evenly over the nut crunch and top with the remaining crunch. Bake for 1 hour. Check to see that the cake is done by jiggling it gently – the middle should be solid not soupy. A toothpick inserted in the center of the cake should come out clean, save for the brown sugar topping. The cake may need an additional 10-15 minutes in the oven.