►Mix cookie crumbs and melted butter in a bowl until mixture resembles wet sand. Press into a 9-inch springform pan and refrigerate for 10 to 20 minutes.
►Heat cream cheese, milk, half-and-half, and sugar in a saucepan over medium heat. Once cream cheese is melted and mixture is smooth, stir in agar powder.
►Pour mixture over chilled crust. Cool at room temperature for 10 minutes, then refrigerate until set, about 6 hours.
►Just before serving, remove cheesecake from pan, spread jam on top, and decorate with berries.