Place the 1 pound bittersweet chocolate in a heatproof mixing bowl, making sure it is chopped into very small, coarsely chopped pieces. If you have larger pieces, you'll have trouble melting the chocolate properly!
In a small saucepan, combine 2/3 cup heavy cream and 1 tablespoon light corn syrup and heat to just under a boil. Remove from heat and pour immediately over the chocolate, letting the mixture sit for a minute or two. Stir with a rubber spatula in a circular motion until all the chocolate has melted. Add 5 tablespoons butter and 1 tablespoon ground cinnamon and stir until it is incorporated. Let the mixture firm up in the fridge for about an hour and a half or so. In a small bowl, whisk together 1/2 cup ground cinnamon, 1/2 cup cocoa powder, 1/2 teaspoon ground nutmeg, 1/2 teaspoon ground all-spice, and 1/4 ground cloves. Set aside.
After about an hour and a half, check on your truffle mixture. If the mixture has hardened but still pliable, it's ready. Use a 1-tablespoon cookie scoop to scoop out a tablespoons worth of chocolate and place it in the shallow bowl filled with ground spice (from the third step). Roll the truffle in the cocoa powder until it is coated evenly. When the truffle is coated evenly, use your palms to roll it into a circular shape. Repeat until the chocolate mixture runs out. Voila! That's it. The truffles will keep in an airtight container in the refrigerator for 2 weeks.