Blackberry Icebox Cake

Ingredients

• 2 pints blackberries, divided
• 1/2 cup blackberry jam
• 1 lemon
• 2 cups chilled heavy cream
• 1/4 cup powdered sugar
• Pinch of kosher salt
• 8 oz. vanilla wafers, divided

Steps

1. From 2 pints blackberries, measure out 2 cups, halve them lengthwise and put in a medium bowl. Keep the remaining berries for decorating later.
2. Mix 1/2 cup blackberry jam with the sliced berries. Use a citrus juicer to juice 1 lemon over them and leave for 10 minutes.
3. With an electric mixer, beat 2 cups heavy cream in a large bowl, starting low and increasing to high speed, until soft peaks form.
4. Beat 1/4 cup powdered sugar and a pinch of salt into the cream just until combined.
5. Line a medium, 6-cup-capacity bowl with plastic wrap, pressing it into the bottom and up the sides with plenty left overhanging. Make a layer of vanilla wafers on the bottom.
6. Spoon about 1/4 cup berry mixture over the wafers. Scoop 1 1/2 cups whipped cream into a small bowl, cover and refrigerate for later. Spread 1/2 cup remaining whipped cream evenly over the wafer and berry layers. Continue layering wafers, breaking to fit if needed, blackberry mixture and whipped cream, increasing amounts as the bowl widens, until all these components are used.
7. Cover by bringing the plastic overhang up and chill at least 24 hours.
8. Unwrap the plastic on top and set a large cake stand or platter firmly over the cake. Flip over, lift off the bowl and peel away the plastic wrap.
9. Whisk the reserved whipped cream back to soft peaks. Use a spoon to dollop it all over the cake, then spread evenly.
10. Halve the reserved berries lengthwise and arrange on top.
11. Cut into 8 pieces for serving.
12. Assembly can be done 2 days ahead, and unmolding and covering with cream can also be done 1 hour ahead. In either case, keep in the refrigerator until the last minute.