For the streusel:
✤1/2 cup (60g) all-purpose flour
✤1/2 cup (42g) sliced almonds
✤1/4 cup (48g) sugar
✤4 tbsp (1/2 stick) unsalted butter, melted
✤1/4 tsp salt
For the rhubarb:
✤3/4 cup (144g) sugar
✤1½ tsp cornstarch
✤1 tsp grated lemon zest
✤1 lb rhubarb, trimmed & cut into ½-inch pieces
✤2 tbsp unsalted butter, melted
For the cake:
✤1 cup (120g) all-purpose flour
✤1½ tsp cardamom
✤1/2 tsp salt
✤1 tsp baking powder
✤1 cup (192g) sugar
✤2 large eggs, room temperature
✤6 tbsp unsalted butter, melted & cooled
✤1/2 cup (120g) light sour cream
✤1 tsp grated lemon zest
✤1 tbsp lemon juice
✤1 tsp vanilla extract
❖Adjust oven rack to lower middle position and preheat oven to 350°F (177°C). Grease an 8-inch square baking pan, line bottom with parchment and grease the paper.
❖For the streusel, stir all ingredients together in a med bowl until well combined. Set aside.
❖For the rhubarb, in a large bowl, whisk together the sugar, cornstarch & zest. Add rhubarb and stir well to coat. Drizzle with the melted butter and stir well. Transfer rhubarb mix to prepared pan and press into bottom of pan, making sure there are no large gaps (pieces may not fit in single layer).
❖For the cake, in a med bowl, whisk together the flour, cardamom, salt & baking powder; set aside.
❖In a separate large bowl, whisk the sugar & eggs until thick and homogenous, about 4-5 min. Whisk in the melted butter until combined. Add the sour cream, lemon zest, lemon juice & vanilla, whisking until combined. Add the flour mix to the wet mix and stir until just combined.
❖Pour batter into pan and spread evenly over rhubarb. Break up streusel with your hands and sprinkle in even layer over batter.
❖Bake until cake is golden brown and toothpick test in center comes out clean, 50-75 min. Transfer pan to wire rack and let cool 20 min. Run a knife around edges of pan to loosen cake, then invert onto a serving platter. Let cool 10 min. Serve warm or at room temperature.
