In a food processor, combine flour, lemon zest, sugar, baking powder, and salt. Pulse for 30 seconds. Add butter and pulse until small pea-sized chunks form.
In a small bowl, mix cream and vanilla. Add to the food processor and pulse until a dough forms.
Divide dough into 9 equal portions. Shape into biscuits about ¾ inch thick. Place on a parchment-lined baking sheet and chill for 20 minutes.
Preheat oven to 425ºF. Bake biscuits for 18–20 minutes until golden brown.
In a bowl, combine strawberries and sugar. Let sit for at least 2 hours. Toss with blueberries before serving.
Whip cream, powdered sugar, and vanilla until medium-stiff peaks form.
To assemble, slice a biscuit in half. Add a layer of berries and whipped cream, then top with the other biscuit half. Serve immediately.