For Raspberry Filling: Cook frozen raspberries over medium heat, stirring constantly, until they come to a boil (4 to 5 minutes). Add xanthan gum and stir well - continue to cook about 1 minute. Remove from heat, cool 10 minutes. Pour into a bowl, loosely cover, and refrigerate.
Preheat oven to 350 degrees. Prepare your pan by using the center removable plate in the Fat Daddio 6 x 3 inch Cheesecake Pan. Trace a circle on parchment paper. Cut out the circle; add the removable bottom back to the pan and spray very lightly with a coconut oil spray. This will keep the parchment paper adhered to the pan bottom. Lay the parchment circle in your pan, smooth out.
Chocolate Crust: Mix THM Baking Blend, unsweetened baking cocoa, mineral salt and sweetener in a medium bowl. Blend well, using a small whisk helps. Once the dry ingredients are mixed well add the melted butter and mix with a fork until you get a nicely coated, crumbly consistency. Pour into your prepared cheesecake pan. Press into the bottom of the 6 inch Fat Daddio cheesecake pan. Bake in preheated oven for 10 minutes. Remove from oven and cool on a cooling rack.
Prepare your Instant Pot by adding 1 cup of water and the rack to the liner. Insert your liner into the instant pot base. Create your aluminum foil sling by folding a 15-18 inch piece of aluminum foil into a strip that is about 3-4 inches wide by 15-18 inches long.
Cheesecake Batter: Combine cream cheese and sweetener in a large mixing bowl. Beat at low speed, scraping the bowl often, until creamy. Add eggs, one at a time, beat only until incorporated.
Once the eggs are incorporated add ¾ cup of sour cream, vanilla and ¼ teaspoon of xanthan gum, gently mix very well scraping the sides.
Quickly prepare your raspberry filling by incorporating ¼ cup of sour cream into your cooked, cooled raspberries. Mix well. Set aside.
Pour half of your cheesecake batter into your prepared pan with the cooled crust. Spread out evenly.
Gently top with raspberry and sour cream filling; gently spreading the filling out evenly to about ¼ inch from edge. Top with remaining cheesecake batter, smooth out. The back of a soup spoon works well to smooth out the layers.
Set your cheesecake pan on and center it in your sling; gently lower into the Instant Pot. Slightly fold over the sling ends so that it does not interfere with the lid locking. Place the cover on the Instant Pot, lock into place and close venting knob to sealing. Hit [Manual] button; adjust using the [-] button to 25 minutes. When the timer beeps allow the pot to NPR (natural pressure release) for 10 minutes. Vent the Instant Pot and carefully remove the cheesecake to a cooling rack.
Dab any water on the top with the corner of a paper towel. Once you have dabbed up any water on the top and sides gently run a thin knife along the edge all the way around to loosen the cheesecake from the sides. this will lessen the chances of a cracking top.
Cool completely, about 2 hours; then loosely cover and refrigerate 8 hours or overnight. Loosen the cheesecake by gently running a knife around the edge, push up the bottom and slide the cheesecake onto a plate. You can gently use a thin spatula to separate the cheesecake from the parchment paper and pan bottom coaching it onto a pretty serving plate.