Preheat the oven to 325°F (163°C).
Prepare the crust by mixing graham cracker crumbs, sugar, and melted butter.
Press the mixture into a lined baking dish and bake for 10 minutes.
In a mixing bowl, beat the cream cheese until smooth.
Add powdered sugar, egg, lemon juice, and lemon zest; mix until smooth.
Pour the cheesecake mixture over the baked crust.
Bake for 25-30 minutes until set and slightly firm to the touch.
Let the cheesecake cool to room temperature before adding the raspberry topping.
Prepare the raspberry topping by cooking raspberries and cornstarch over low heat.
Spread the raspberry topping over the cooled cheesecake, then chill for at least 2 hours.
Cut into squares and serve chilled.
