The raspberries should be completely thawed before starting. Place them in a food processor and puree them on high then pour the puree through a fine mesh sieve into a medium sized pot. Press as much ‘juice’ as you can out of the sieve. Discard the seeds.

Set the pot with the puree over medium low heat and cook until the puree reduces to a little less than half its volume, it should be darker and thick (but not like jam). Remove from the heat and set aside. You can make this up to a week ahead of time if stored in an airtight container in the fridge.

Preheat the oven to 350 F. Grease an eight inch round cake pan (it should be about 3 inches tall) and press a sheet of parchment into the bottom and sides of the pan. Use metal clips to hold the parchment in place.

Grind the graham crackers into fine crumbs. In a large bowl mix the crumbs with the melted butter, powdered sugar and a pinch of salt. Stir until well mixed; when you squeeze crumbs together in your palm they should hold shape.

Press half of the crumbs into the bottom of the pan and the other half up the sides. Parchment makes this slightly difficult so just do your best to make an even layer. Use a jar or measuring cup to pack the crumbs into shape.

Bake the crust for 10 minutes. Then set aside to cool.

Set the room temperature cream cheese in the bowl of a stand mixer fitted with the paddle attachment (or use a hand mixer and a large bowl). Press the cream cheese into the bowl using a rubber spatula, this helps to remove lumps. Add the salt, vanilla and sugar and beat on low until smooth. Stop to scrape the bowl’s bottom and sides to ensure even mixing.

Add in the sour cream and cooled, reduced raspberry puree and mix (again on low) until smooth. Stop and scrape as needed. Add the eggs and powdered sugar and mix again, just until incorporated (avoid over mixing in the eggs - this can cause the cheesecake to collapse).

Pour and press the filling through a fine mesh sieve into a bowl to remove any lingering lumps in the filling. Pour the filling into the crust and smooth into an even layer. Set the cheesecake in a larger pan (a 9x13 cake pan works well) and fill the larger cake pan with water so the water level comes level with the cheesecake in the smaller cake pan.

Reduce the heat to 325 F and set the cheesecake (in its water bath) in the middle rack of the oven. Bake until the outer rim is set but the middle still wobbles when the pan is gently shaken; about 45 minutes (use visual cues to check for doneness, do not rely on timings listed). If you have an instant read thermometer, insert it into the center: a cheesecake is done baking at 150 F.

Turn off the oven and leave the oven door open. After ten minutes, remove the cheesecake (still in its water bath) and set on the counter. Once it’s at room temperature, set in the fridge to chill for at least six hours, but preferably overnight.

The day of serving, make the whipped cream topping and add fresh berries. Store the leftovers in the fridge, in an airtight container where they’ll keep for around five days.