A simple, one-layer Hazelnut Raspberry Crumb Cake to serve over the holiday season! Infused with brown butter and lightly spiced with cardamom and cinnamon, this crumb cake is topped with a thick layer of St. Dalfour Red Raspberry Fruit Spread and finished with a crisp and buttery hazelnut crumb topping. Serving and Storage Tips: This crumb cake is best served slightly warm or at room temperature the day it is baked. However, leftovers can be wrapped tightly in foil, transferred to a Ziplock bag, and kept out at room temperature for 1-2 days.
Preheat the oven to 350°F (175°C) with a rack in the center position. Lightly grease an 8-inch (20-cm) square cake pan with baking spray and line with a parchment paper overhang (*this makes it easy to lift out the cake after baking). Set aside.
Prepare the Hazelnut Crumb Topping: In a medium bowl, whisk together the all-purpose flour, dark brown sugar, cardamom, and salt. Add the softened, cubed butter and toss until coated. Using your fingertips, cut the softened butter into the dry ingredients, pressing the mixture together with your fingertips until small and medium-size crumbs form. Stir in the finely chopped hazelnuts. Place the crumb topping in the refrigerator to chill while you prepare the cake batter.
Prepare the Cake Batter: Cut the butter into quarters and place in a small saucepan. Set over medium-low heat. Melt and continue cooking the butter, whisking it continuously as it bubbles, until the solids start to brown and it becomes very fragrant. Remove from the heat and immediately transfer the browned butter (along with any brown bits from the bottom of the pan) to a large mixing bowl. Allow the butter to cool slightly - it should be just lukewarm - before proceeding.
As the butter is cooling slightly, whisk the all-purpose flour, baking powder, cardamom, cinnamon, baking soda, and salt in a separate medium bowl. Set aside.
Add the lemon zest, dark brown sugar, granulated sugar, and eggs to the bowl with the slightly cooled brown butter. Whisk together vigorously for a minute or so, until smooth, pale, and just barely frothy. Add the sour cream and vanilla to the bowl, whisk until incorporated and smooth.
Add the dry flour mixture to the wet ingredients. Stir together with a whisk until just absorbed, switching to a rubber spatula to scrape down the edges of the bowl and ensure all of the dry ingredients have evenly incorporated. Do not over mix.
Transfer the batter to the greased, parchment-lined pan. Use an offset spatula to spread the batter into a smooth, even layer. Dollop spoonfuls of St. Dalfour Raspberry Fruit Spread across the batter, then use an offset spatula to spread it into even, thin layer - extending to the edges of the pan. Sprinkle the hazelnut crumb topping evenly over the jam layer.
Bake for 45 to 55 minutes or a cake tester inserted in the center comes out clean. Baking Note: The fruit spread and crumb topping will create natural caverns, so do not worry if the surface of the baked cake isn't completely even - this is to be expected. Set the pan on a rack and cool for 10 to 15 minutes; then use the edges of the parchment paper to lift the cake out of the pan. Place on a rack to cool completely (or serve slightly warm).
Serving and Storage Tips: This crumb cake is best served slightly warm or at room temperature the day it is baked. However, leftovers can be wrapped tightly in foil, transferred to a Ziplock bag, and kept out at room temperature for 1-2 days.
Tips for Success:
Mix up the flavor of these crumb bars by swapping the Raspberry Fruit Spread with other St. Dalfour Fruit Spreads, such as : Blackberry, Peach, Apricot, or Strawberry.
Substitute the hazelnuts with equal parts (by weight) pecans or walnuts.