Blueberries are one of my favorite fruits. I have several new Southern high bush blueberry plants in my garden this year. Their flavor is rich and sweet — but subtle in a dessert. To get the blueberry flavor and color I was after, I turned to freeze dried blueberries to add big blueberry flavor to this luscious spongecake roll. Adding whole fresh blueberries adds texture and interest to this treat.
The spongecake is simple and fluffy, and rolls up nicely without cracking. For this cake you’ll need a 15 inch jellyroll pan and parchment paper.
The Swiss meringue buttercream filling gets its amazing color and flavor from pulverized freeze dried blueberries. Freeze Dried blueberries are super light in weight, but retain the shape of a fresh blueberry and have a crisp, crunchy texture. I bought the freeze dried blueberries from my local market, then ground them in a spice grinder until a fine powder. I used the entire contents of a packet of freeze dried blueberries (about 2 cups to begin with) and ended up with about 2/3 cup ground blueberries.
The proportions aren’t exact — just add the amount of pulverized blueberries you like to achieve the flavor and color you desire. Enjoy!
(serves 8 – 10)
4 large eggs
7 oz (1 cup) sugar
4/1/2 oz (1 cup sifted) unbleached all purpose flour
1/4 tsp. sea salt, fine
1 TB vanilla extract
2 TB water
2 TB butter, melted
Preheat over to 375. Grease and flour the sides of a 15″ jelly pan roll, then fit a sheet of parchment paper, also greased and floured, to the bottom of the pan.
Using the whip attachment to your mixer, beat eggs on medium high speed for a minute. Add sugar, then beat for several minutes, or until very light and fluffy. Reduce mixer speed to low, and add in vanilla and water.
Sift together flour and salt. Gently fold flour/salt mixture into the egg mixture until incorporated. Gently stir in the melted butter.
Pour batter into the prepared pan and bake for 13 – 17 minutes or until light golden brown, and the middle of the cake springs back when pressed.
Allow cake to cool in the pan for a couple minutes, then score the edges of the pan to release the sides of the cake. Invert the cake onto a clean cotton or linen dishcloth that has been lightly dusted with powdered sugar. Gently roll up the cake long-wise in the towel and allow to cool, seam side down.
Blueberry Swiss meringue buttercream
3 egg whites
6 oz sugar
8 oz unsalted butter, room temperature
2/3 cup finely ground freezedried blueberries
3/4 cup fresh blueberries – for the assembly of the dessert
Combine the egg whites and sugar in a heatproof mixing bowl. Place over a pan with 1 inch simmering water, and whisk the egg/sugar mixture until the sugar has dissolved completely into the egg whites and the mixture is about 140 degrees. (more info here)
Whip the hot egg/sugar mixture on high heat until fluffy, white, and cooled to almost room temperature. Remove the whip attachment and replace it with the mixing paddle. Add the butter one TB at a time while paddling on low. Gently fold in the ground blueberries with a spatula.
To assemble the cake, unroll the spongecake from the towel. Apply the blueberry buttercream over the inward side of the rolled cake and spread evenly, leaving a one inch margin on one long side. Sprinkle the fresh blueberries evenly over the buttercream. Roll up the spongecake longways, and place on a serving tray, seam side down. Dust with additional powdered sugar if desired. Allow to cool in the fridge for at least a 1/2 hour, then serve by slicing the roll.