- To make the Blackberry Jam, add the blackberries, sugar, and lemon juice to a small saucepan. Bring the mixture to a boil, then reduce the heat to medium. Let the blackberries simmer, using the back of the spoon to help the blackberries break apart and dissolve. Cook the mixture for about 10 minutes, stirring every so often, until the blackberries have softened up, and the sugar has turned into a thick syrup.
- At this point, mix the cornstarch and water in a small separate bowl, until the cornstarch dissolves.
- Then add the dissolved cornstarch to the blackberries and immediately begin to stir.
- Cook for another 1 to 2 minutes, while stirring non-stop, until the jam is very thick.
- Then pour the jam through a strainer to retain the seeds.
- Press down on the seeds through the strainer to release as much liquid as possible from the blackberries.
- Let the jam cool down completely. It can be made ahead up to 4 days.
Blackberry Russian Buttercream
- Make sure the butter is at the appropriate consistency, which should be at room temperature. The butter should have a nice shape, not be too soft, but not cold either. It’s ideal if the butter is from 68 to 72ºF.
- Beat the butter with an electric mixer, at medium-high speed, for 5 minutes.
- Add the sweetened condensed milk in. Beat with the mixer on medium speed until the frosting becomes creamy and thick.
- It might take a while for the buttercream to come together and become thick, especially if the butter was on the soft side, or if the kitchen is too warm.
- In that case, you can place the bowl in the fridge for 5 to 10 minutes and then try to whip the buttercream again to see if it comes together.
- Add the blackberry jam and stir to combine.
- Place the buttercream in a piping bag fitted with the tip of choice, I used a large round tip.
Blackberry Whipped Cream
- Make sure the whipping cream is super cold from the fridge.
- Begin whipping on low, increase the speed to medium-high after 30 seconds, and continue to whip the heavy cream for about 2 minutes, until stiff peaks form.
- Once that happens, add the sweetened condensed milk to the bowl and mix until incorporated.
- Add the blackberry jam and mix to combine.
- Lay 12 cookies next to each other forming a rectangle.
- Pipe dots of the Blackberry Russian Buttercream all around the edges of the cookie base.
- Then spread some of the Blackberry Whipped Cream on top. And drizzle some Blackberry Jam over the whipped cream.
- I put my jam in a piping bag and used that to drizzle the jam over the whipped cream, but you can definitely just use a spoon.
- Lay another 12 cookies on top of the filling.
- Repeat another piping of the Blackberry Russian Buttercream around the edges of the cookie base. Do the same for the other elements: some Blackberry Whipped Cream in the center, and more jam on top.
- Repeat this with one more layer.
Finally, time to decorate the top.
- I piped dots of frosting around the edges of the cake, and then put some blackberries, chocolate straws, and crisp pearls on top. And I also decorated the blackberries with edible gold leaf.
- Let the cake sit at least overnight before serving, the longer the better, to give the cake a chance to absorb the textures and flavors. Before serving let the cake sit at room temperature for 10 minutes or so.
Recipe by our friend Camila @PiesandTacos