• Place the chopped chocolate in a medium-sized heatproof bowl. Set aside until needed.
• In a small saucepan over medium heat, bring the cream to a boil. As soon as it begins to boil, remove the cream from heat. 
• Pour the hot cream over the chopped chocolate and allow the mixture to sit, untouched, for a minute. Then whisk until smooth. 
• Stir in the butter and Grand Marnier and vigorously whisk until smooth and shiny.
• Set aside and cool to room temperature. Then tightly cover the bowl with plastic wrap and refrigerate for 2 and ½ hours or until firm enough to scoop.
• Place the cocoa powder in a wide shallow dish and set aside.

For the Tempered Chocolate:

• Fill a medium pot one-third full with water and bring it to a very low simmer over medium heat. Place a heatproof bowl that will fit on top of the pan snugly, but will not touch the simmering water, on top of the pan. 
• Reduce the heat to low and place two-thirds of the chocolate into the bowl. Place a candy thermometer into the chocolate and let it melt, stirring frequently with a silicone spatula. Do not let the temperature of the chocolate exceed 120°F.
• Once the chocolate has fully melted, carefully remove the bowl from heat, but keep the pot of simmering water on the burner. Wipe the bottom of the bowl to remove any condensation.
• Stir in the remaining chocolate, a little bit at a time, allowing what you've added to completely melt before adding more.
• Set aside and allow the chocolate to cool to 84 degrees (F). Once the chocolate has reached this temperature, reheat it briefly by placing the bowl back over the simmering water for about 10 seconds, or until it’s between 89 and 91 degrees (F). Do not let the temperature exceed 91°F! 
• Remove the bowl from heat once you have reached the correct temperature. The chocolate should be smooth and glossy, with no streaks.

Assembly:

• Before you begin, make sure you have enough room in your refrigerator for both baking sheets, as the truffles must chill again before being dipped in the chocolate coating.
• Line two large baking sheets with parchment paper and set them aside.
• Measure 2 teaspoons of the truffle filling and quickly roll it between your hands to form a ball. Transfer to the prepared baking sheet, and repeat with all truffles. Refrigerate the rolled truffles for at least 1 hour before dipping in the chocolate. Or roll in cocoa powder at once, then refrigerate.
• To dip, remove the chilled truffles from the refrigerator. Using a fork or candy dipper, dip each truffle into the chocolate then lift it up over the bowl, allowing excess chocolate to drip back into the bowl before dunking it back in again, then lifting it out and allowing any excess chocolate to drip back into the bowl. Once the truffle has been double dunked, carefully transfer it back to the parchment paper lined baking sheet.
• Sprinkle the top of each truffle with a little bit of the crushed flaky sea salt. 
• Set aside and allow the chocolate to set before serving, about 1 hour. Store in an airtight container, at room temperature, for up to 1 week.