Updated May 2, 2019Chatelaine
cold, unsalted butter, cubed
- Position rack in centre of oven, then preheat to 325F. Spray a 9-in. springform pan with oil, then line bottom with parchment.
- Streusel: Combine flour and sugar in a medium bowl and, using fingers, work in butter until mixture is crumbly. Stir in pecans.
- Cake: Whisk flour, baking powder, baking soda, cinnamon, cardamom and salt in a medium bowl.
- Beat butter and sugar in a large bowl, using an electric mixer on medium, until fluffy, about 3 min. Beat in eggs, one at a time, scraping side of bowl as needed until combined, then vanilla. Beat in half of flour mixture, then sour cream, then remaining flour mixture, until just blended. Fold in rhubarb.
- Transfer batter to prepared pan, smoothing top with a spatula. Sprinkle with streusel mixture.
- Bake, covering with foil if nuts are browning too quickly, until a cake tester inserted into centre of cake comes out clean, about 1 hr 20 min. Let cool in pan on rack for 10 min, then release springform ring and let cool completely, about 1 hr. Cake will keep well, covered, at room temperature for up to 3 days.
Kitchen tip: For people with nut allergies, skip the streusel topping and simply dust the cake with icing sugar before serving.