16 ounces good-quality milk or semisweet chocolate, finely chopped
1 cup miniature marshmallows
1 cup coarsely chopped walnuts
1. Line a baking sheet with parchment paper and set aside.
2. Melt the chocolate over a double boiler (or in 30-second intervals in the microwave on 50% power, stirring after each). Once the chocolate is melted, remove from the heat and let sit for a few minutes to cool slightly, stirring occasionally. Add the marshmallows and walnuts and stir to combine.
3. Spread the chocolate mixture onto the prepared pan in an even layer, covering about a 7x7-inch space. It doesn't have to be perfect, but that's a good guideline.
4. Refrigerate for at least 30 minutes, or until set.
5. Using a sharp knife, cut the bark into pieces. Store in an airtight container in the refrigerator.
Note: I recommend Ghiradelli or Lindt chocolate.