Set up a double boiler or place a heatproof bowl over a saucepan of simmering water. Melt the dark chocolate, stirring occasionally until smooth.
Remove from heat and stir in the coconut oil, liquid Stevia, and ground cinnamon until fully combined and glossy.
Fold in the fresh orange zest, orange extract, and chopped walnuts.
Stir until the walnuts are evenly coated in the chocolate mixture.
Using a teaspoon, drop spoonfuls of the mixture into mini paper muffin liners or onto a baking sheet lined with parchment paper.
Refrigerate for at least 4-6 hours, or until the clusters are completely firm. Store in an airtight container in the refrigerator.
Taste the chocolate mixture before adding the walnuts.
Adjust the amount of Stevia to your personal preference, as 100% cocoa is very intense.