Line an 8 x 8-inch baking pan with parchment paper.
There are two ways to make the nama chocolates. For a more purely chocolate confection, in a saucepan, heat the heavy cream and butter to 120°F. Remove from heat. Add the chocolate to a large heatproof bowl and microwave for 15 seconds. Pour the cream into the softened chocolate to temper it. Add the optional liquor or vanilla extract and a pinch of salt. Whisk until creamy and homogeneous. Refer to the final step.
The second way to make the nama chocolates, which has more matcha flavor, is to heat the heavy cream and butter to 110°F in a saucepan, until the butter has melted. Immediately remove from heat and mix in the white chocolate, vanilla extract, and salt until incorporated and creamy. Sift in the matcha and whisk until homogeneous. Go on to the final step.
The final step: Pour the chocolate mixture into the prepared pan. Even and smooth out the top of the chocolate. Tap the pan against the counter to get rid of air bubbles. Cover with plastic wrap and refrigerate for at least 3 hours.
Depending on how big you want the nama chocolates to be, you can slice the chocolate into 24-36 equal pieces. Dust with either the cocoa or matcha. Feel free to garnish with edible gold flakes or sea salt flakes.
Nama chocolates should be refrigerated in an airtight container and eaten within 5 days. Take care not to overheat the heavy cream or the chocolate will separate.