In a food processor combine the graham crackers crumbs, brown sugar and melted butter. Pulse until combined. Press the mixture firmly in the bottom of a 7 inch round springform pan. Set aside.
For the filling: In a stand mixer, using the paddle attachment, combine the cream cheese, granulated sugar, and sour cream. Beat on medium speed until smooth. About 3 minutes. Scrap down sides of bowl and add eggs, lemon juice and vanilla extract. Beat on medium-high for an additional minute. Pour filling over the prepared crust.
Pour 2 cups of water into an Instant Pot and insert a steam rack. Place cake into a silicon pressure cooker sling and lower into the Instant Pot. If you do not have a steam rack. Use tin foil create a "cover" for the bottom of the pan and comes at least half way up the sides, to prevent water from penetrating the pan. Tuck any foil edges over the top of the pan.
Lock the lid into place and turn the valve to sealing. Set the Instant Pot to pressure cooker at high pressure for 28 minutes.
Once the pressure cooking is complete, let the steam release naturally for 15 minutes. Then turn the valve to venting to release any additional residual steam. Remove lid and lift out the cake pan using the silicone sling handle. Let the cake cool, then cover and refrigerate until set. At least 2 hours. I would suggest overnight, if possible.
To make sour cream topping, combine sour cream and confectioners' sugar and whisk until smooth. Add vanilla extract and whisk until combined. Cover and refrigerate until ready to use.
To serve, remove the pan sides and spread sour cream topping evenly on top of the cake. Finally, place raspberries so they cover the entire top of the cheesecake and sift confectioners' sugar on top if desired! Then enjoy!