Stir together cookie crumbs, sugar and butter; press into bottoms of
6 ½-cup (125 mL) canning jars or heatproof ramekins. Refrigerate until firm, about 10 minutes.
In a large bowl, beat cream cheese until fluffy. Gradually beat in sugar, scraping down side. Beat in yogurt, lemon zest and vanilla until smooth. Beat in egg just until combined. Spoon over crust.
Fill a rectangular 6- to 7-quart (6 to 7 L) slow cooker with enough hot water to come ½ inch (1 cm) up side. Arrange jars, uncovered, in a slow cooker. Cover top of slow cooker with a triple layer of paper towels; cover with lid. Cook on low until set but still slightly jiggly in centre, about 1½ hours. Carefully remove jars to rack with pot holders or tongs.
Cherry berry topping
Meanwhile, in a saucepan, heat cherries, raspberries, strawberries and sugar over medium heat, stirring occasionally and gently, until fruit is softened and liquid starts to release, about 5 minutes. Mix cornstarch with lemon juice and 1 tbsp (15 mL) cold water. Stir into fruit mixture. Cook, stirring gently, until bubbling and thickened, about 2 minutes.
Spoon sauce over top of warm cheesecakes. Let cool. Cover and refrigerate until chilled, 4 to 6 hours. (Make-ahead: Refrigerate for up to 2 days.)
Nutrients per serving: 247 calories, 9 g protein, 5 g fat (2 g saturated fat), 44 g carbohydrates, 2 g fibre, 18 mg cholesterol, 338 mg sodium