Place the berries in a glass bowl. Sprinkle 1 tablespoon of the sugar, lemon juice, and zest over, toss gently, and let them sit at room temperature for 15 minutes. Remove a few berries from the bowl and set aside for garnish. Using the back of a fork, mash the rest of the berries a little bit, so that you have a kind of chunky syrup. Let that sit for another 15 minutes.

Beat the cream and ¼ cup sugar for about 2 minutes, until stiff peaks form. Fold in the yogurt. Pour the crushed berries and juices into the bowl with the cream and fold just once or twice, so that streaks of cream and berries remain. 

Spoon into bowls, garnish with the reserved whole berries, and serve with shortbread cookies.