CRUST
2 cups crushed pretzels
3 tablespoons sugar
12 tablespoons (1 1/2 sticks) unsalted
butter, melted
FILLING
8 ounces cream cheese
3/4 cup plus 1 tablespoon sugar
7 ounces plain Greek yogurt (not fat-free)
2 teaspoons vanilla extract
2 3-oz. packages strawberry gelatin
1 16-oz. package frozen unsweetened sliced
strawberries
1 16-oz. package frozen unsweetened
blueberries
3/4 cup heavy cream
Make crust: Preheat oven to 400ºF; mist a
9-by-13-inch baking pan with cooking spray. Place crushed pretzels in bowl of a
food processor. Add sugar and melted butter and pulse to combine. Press pretzel
mixture into baking dish and bake for 8 minutes. Transfer to a wire rack and
allow to cool completely, about 20 minutes.
Make filling: Using an electric mixer on
medium speed, beat cream cheese with 3/4 cup sugar until well blended, about 2
minutes. Fold in yogurt and vanilla. Spread over cooled pretzel crust, cover
with plastic wrap and chill for at least 2 hours.
In a large bowl, dissolve both packages of
gelatin in 2 cups boiling water. Stir in strawberries and blueberries and pour over cream
cheese layer. Chill until firm, 2 to 3 hours.
Whip cream until soft peaks form. Add
remaining 1 Tbsp. sugar and continue whipping until stiff peaks form. Cut tart
into squares and serve with whipped cream.