Prepare cream mixture: In a small saucepan, heat the heavy cream and butter over medium heat until the butter melts and the mixture begins to simmer. Do not boil.

1. Add pumpkin and spices: Stir in the pumpkin puree and pumpkin spice blend (or cinnamon, nutmeg, and ginger). Whisk until smooth.
2. Mix in vanilla: Remove from heat and stir in vanilla extract.
3. Combine with chocolate: Place semisweet or dark chocolate in a heatproof bowl. Pour the warm pumpkin cream mixture over the chocolate. Let it sit for 1-2 minutes, then stir until smooth. If the mixture is too runny, add powdered sugar to thicken it.
4. Cool and chill: Allow the mixture to cool to room temperature. Then, transfer to the refrigerator for 30 minutes, or until firm enough to scoop and roll.
5. Melt white chocolate: While the filling chills, melt the white chocolate in a heatproof bowl using a double boiler or microwave in 30-second intervals, stirring each time. Let it cool slightly.
6. Form balls: Scoop small amounts of the pumpkin chocolate filling and roll into balls. Place on a parchment-lined baking sheet.
7. Dip in chocolate: Dip each ball into the melted white chocolate, ensuring it is fully coated. Let any excess drip off and return the dipped chocolates to the sheet.
8. Chill again: Refrigerate for 30 minutes to allow the coating to firm up.
9. Serve: Serve chilled or at room temperature. Store in an airtight container in the refrigerator for up to 2 weeks.