This recipe uses a boxed cake mix, a fresh blueberry/blackberry sauce, and homemade flavored whipped cream. It is a gorgeous and tasty cake to take to a picnic or Summer potluck.
1 ½cupsfresh or frozen blueberriesplus extra for decorating
1 ½ cupsfresh or frozen blackberriesplus extra for decorating
½Cupgranulated sugar
1Tablespooncornstarch
⅛ Teaspoonfine salt
2Teaspoonsfresh lemon juice
2Cupsfluid heavy cream
3Tablespoonsconfectioners’ sugar
2Teaspoonsvanilla extract
Instructions
Preheat oven to 350 degrees. Grease a 9-by-13-by-2-inch baking pan with cooking spray or butter. In a stand mixer mix the cake batter according to the recipe on the box (usually includes some water and 3 eggs)Bake for 35 minutes.
1 Box Cake mix, water, 3 eggs
While the cake is baking, in a medium saucepan over high heat, stir together the blueberries, blackberries, sugar, cornstarch and salt. You may need to add a little water (~1/2 cup)Bring to a boil and cook, stirring occasionally, for about 5 minutes. Reduce the heat to medium-high and simmer until the puree thickens and the berries begin to break down, about 10-15 minutes.Remove from the heat and let cool for about 5 minutes. Transfer the puree to a blender and blend until thick and pourable. Stir in the lemon juice. Set aside 3 to 4 tablespoons of puree in a small bowl.
1 1/2 cups fresh or frozen blueberries, 1 1/2 cups fresh or frozen blackberries, 1/2 Cup granulated sugar, 1 Tablespoon cornstarch, 1/8 Teaspoon fine salt, 2 Teaspoons fresh lemon juice
Allow the cake to cool just slightly (5-10 minutes) and then begin poking the cake with the end of a wooden (or silicone) spoon (see headnote). Poke 1 row of holes at a time (about 4 hole across). The holes should be about 1 inch apart Press the spoon handle into the cake until it feels like you may have hit the bottom of the pan. Spoon or drizzle the puree into the holes, filling each one up. The cake absorbs the puree quickly, so refill the holes with the puree until you run out, or until the cake seems adequately filled. Refrigerate the cake for at least 2 hours or overnight.
When ready to serve, in the bowl of a stand mixer fitted with the whisk attachment combine the cream, sugar and vanilla and beat on medium to medium-high speed until medium to stiff peaks form, about 5 minutes.
After cake is chilled, run a butter knife around the sides of the pan and, using spatulas under the cake, lift the cake out of the pan. (May need 2 people to do this). Place the cake on a rectangular serving platter or cutting board. Before frosting the cake, use a small paring knife to mark the location of the the center of each row of holes. This will allow you to know where to slice the cake for presentation (so you can see the berry filling down the sides). Generously top the cake with whipped cream (leaving the sides unfrosted). Place a small spoonful of reserved berry sauce on the whipped cream topping and pull the spoon through it to leave berry swirls on the top. When ready to slice the cake, check the sides of the cake where you marked the center of the location of the holes.Sprinkle a few blueberries over the cake, if desired, slice along the rows of holes and serve.
Video
Notes
** nutritional analysis is based on a piece approximately 2 1/3 inches by 3” in a 9 x 13 inch baking dish.Storing Notes: The berry puree can be refrigerated for up to 3 days. The unfrosted cake can be frozen for up to a week. The completed cake with whipped cream topping will keep just fine in the refrigerator for about a week, if kept in a covered dish.