In a medium bowl, combine the crushed oreos and melted butter.
Pour the mixture into a 9 inch springform pan*, and pack it down tightly and evenly onto the bottom of the pan. The bottom of a glass or measuring cup works well to make sure it’s tightly packed. Place the pan in the freezer while you prepare the filling.
Filling
Place 4 cups of raspberries and the lemon juice in a small saucepan over medium heat. Cook for about 5 minutes, mashing with a fork until fairly smooth. Into a microwave-safe bowl, strain the puree with a mesh strainer, pushing it through with a spoon or rubber spatula. You will end up with about 1 cup of raspberry puree. Sprinkle 2 packages of gelatin over the puree and set aside to bloom.
In a stand mixer fitted with the whisk attachment, beat the cold heavy cream on medium high speed to stiff peaks, about 5 minutes.*
Scrape the whipped cream into a bowl and place in the refrigerator.
Clean the stand mixer bowl and beat the cream cheese and sugar together on medium speed until smooth, scraping down the bowl as needed, 2-3 minutes.*
Place the bowl of raspberry puree in the microwave. Heat for 30 seconds, stirring every 10 seconds, until the gelatin is melted. The mixture should be just warm to the touch, not hot.*
Add the raspberry gelatin mixture and vanilla extract to the mixer bowl and beat until well incorporated, another 2-3 minutes.
Remove the bowl from the stand and slowly and carefully fold in the whipping cream until combined.
Remove the crust from the freezer and pour the filling into the pan. Smooth the top with a spoon or offset spatula.
Cover with plastic wrap and chill for a minimum of 8 hours, or overnight.
Run a knife inside the rim of the springform pan to loosen the cheesecake before removing it.
Serve topped with extra berries and whipped cream if you like.
Notes
*You can crush the oreos in a food processor, or put them in a zip-top bag and crush with a rolling pin*for a perfectly smooth cheesecake, make sure your cream cheese is at room temperature. Cold cream cheese tends to stay lumpy no matter how long you beat it for. Set it on the counter for at least a couple of hours before using it.* Be sure to whip the cream to stiff peaks: Stiff peaks are important for the filling to set properly. Basically the peaks should not droop at all when you lift the beater. *If you don't have a springform pan, feel free to use a 9" deep dish pie pan, although you might end up with a little extra filling).