Line mini muffin pans with paper liners. Fill with assorted nuts.
Add the chocolate to a glass microwave-safe bowl. If using chocolate baking bars, chop the chocolate first.
Microwave the chocolate at 50% power for 15- or 30-second intervals, stirring in between each interval, until the chocolate is completely melted. (Note 2)
Pour the chocolate into each paper liner, covering the nuts. Gently shake the pans and tap them lightly on the counter to settle the chocolate down around the nuts.
If desired, sprinkle with flaked salt before the chocolate sets up.
Let sit at room temperature for 30-60 minutes until fully set.
Notes
To roast raw nuts: Add raw nuts to a sheet pan. Bake in a 350-degree oven for 7-10 minutes, shaking the pan every 2-3 minutes. When the nuts become fragrant, they are ready. The nuts should not brown. Cool then proceed with the recipe.
To melt chocolate using the double boiler method: Place a heat-safe glass bowl over a pot of gently simmering water. Make sure the bottom of the bowl doesn't touch the water. Add the chocolate to the bowl and stir until completely melted. TIP: If using baking chocolate bars, chop the chocolate before adding it to the bowl to speed up the melting process.
If you don't have mini muffin pans, you can make these clusters free-form on a parchment-lined baking sheet. Toss the nuts in the melted chocolate to coat. Transfer small spoonfuls of the chocolate-nut mixture to the prepared baking sheet. Allow to cool and set.