In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer. Do not let it boil.
Remove the saucepan from heat and add the semi-sweet chocolate chips. Let it sit for 2-3 minutes to allow the chocolate to melt.
Stir the mixture until smooth and fully combined. Add the vanilla extract and mix well.
Transfer the chocolate mixture to a bowl and cover it with plastic wrap. Refrigerate for at least 2 hours, or until firm.
Once the mixture is firm, use a small cookie scoop or your hands to form small balls (about 1 inch in diameter).
Roll each truffle in cocoa powder, crushed nuts, or shredded coconut to coat.
Place the coated truffles on a parchment-lined baking sheet.
Refrigerate the truffles for another 30 minutes to set before serving.