Step 1: Melt the Ganache Base
In a double boiler or microwave-safe bowl, melt the 6 ounces of chopped white chocolate and the heavy cream together. Stir frequently until the mixture is completely smooth. Set this aside to cool slightly so it doesn’t melt the cream cheese later.

Step 2: Beat the Cream Cheese Mixture
In a large mixing bowl, beat the softened cream cheese, sour cream, granulated sugar, cornstarch, and vanilla extract using a hand mixer or stand mixer until the mixture is creamy and smooth.

Step 3: Combine Ingredients
Slowly add the cooled white chocolate ganache mixture and the seedless raspberry jam to the cream cheese bowl. Beat everything together until well combined and uniform in color.

Step 4: Chill the Filling
Place the bowl in the refrigerator and chill for at least 2 hours. This step is crucial as the filling must be firm enough to scoop and hold its shape.

Step 5: Scoop and Roll
Line a baking sheet with parchment paper. Using a small spoon or melon baller, scoop small portions of the chilled filling and roll them into balls with your hands. Place them on the prepared baking sheet.

Step 6: Melt the Coating
Melt the 12 ounces of chopped white chocolate in a double boiler or microwave. Stir frequently until smooth. Be careful not to overheat it, or the chocolate may seize and become grainy.

Step 7: Dip the Truffles
Working one by one, dip each chilled truffle ball into the melted white chocolate. Use a fork to lift it out, gently tapping the fork against the side of the bowl to shake off excess chocolate. Transfer the coated truffle back to the parchment-lined baking sheet.

Step 8: Set and Serve
If using toppings, sprinkle them on while the coating is still wet. Refrigerate the truffles for at least 30 minutes, or until the chocolate coating is completely set and firm.