Filling & Topping
3/4 cup heavy cream
1/3 cup sugar
1 cup nonfat vanilla Greek yogurt
3 cups blackberries, divided
2 teaspoons lemon zest
To prepare the crust: Preheat oven to 350°F. Coat a 9-inch pie pan with cooking spray.
1. Process cookies in a food processor until finely ground. Add oil and process until well combined. Using your fingertips or the back of a spoon, press the crumb mixture into the bottom and up the sides of the prepared pan.
2. Bake until just set, 10 to 12 minutes. Transfer to a wire rack to cool.
3. To make the filling: Whip cream in a medium bowl with an electric mixer until starting to thicken. Add sugar and continue whipping until stiff peaks form. Gently fold in yogurt.
4. Clean out the bowl of the food processor and puree 2 cups blackberries. Pour the puree through a sieve into the yogurt-cream mixture, pressing on the solids to strain out as much of the puree as possible. Add lemon zest and gently fold the flavorings into the yogurt-cream mixture.
5. Spread the flavored yogurt-cream mixture into the cooled crust. Top with the remaining 1 cup blackberries. Freeze until very firm, at least 5 hours. To serve, let the pie stand at room temperature until softened slightly, about 15 minutes, before slicing.
Tips & Notes
Make Ahead Tip: Once frozen, wrap airtight and freeze for up to 1 week. Let stand at room temperature for about 15 minutes before serving.
For a healthier cookie crust, choose cookie brands without any partially hydrogenated oils (trans fats). We like Mi-Del ginger and chocolate snaps. Look for them in the natural-foods section of well-stocked supermarkets and at natural-foods stores.