In a mixing bowl, combine the digestive biscuit crumbs with melted butter. Stir until the mixture resembles wet sand.
Press the mixture firmly into the bottom of a 9-inch springform pan, creating an even layer. Use the back of a measuring cup to pack it down tightly. Place the crust in the refrigerator to set while you make the filling.
In a large bowl, beat the softened cream cheese with the powdered sugar and vanilla extract until smooth and creamy, ensuring there are no lumps.
In another bowl, whip the heavy cream until soft peaks form. Gradually fold the whipped cream into the cream cheese mixture gently, being careful not to deflate the whipped cream.
Fold in the sliced strawberries into the cheesecake mixture, reserving a few for garnish. Pour the mixture into the prepared crust, smoothing the top with a spatula.
Cover the pan with plastic wrap and refrigerate for at least 4 hours or overnight for the best set.
Once set, gently warm the strawberry jam in a small saucepan until melted. Drizzle it over the top of the cheesecake and arrange the reserved strawberry slices on top for decoration.
Carefully remove the springform pan and slice the cheesecake. Garnish with fresh mint leaves if desired.