Line an 8x8-inch square dish with parchment paper. Fit two sheets so that they are as wide as the dish and then overlap them cross-wise, completely covering the dish and overhanging the edges, forming a sling that can be used to lift the set fudge out.

Combine the chocolate, cream, butter, and salt in a microwave-safe bowl. Microwave on 50% power for 2-4 minutes, stirring occasionally with a spatula. Continue heating in 20 second intervals stirring between each until completely smooth. Stir in the peppermint extract. Alternatively, you can melt the mixture in a large bowl over a pot of simmering water (make sure to use at least one inch of water at a bare simmer that does not touch the bottom of the bowl).

Pour the ganache into the prepared pan and set sit until room temperature, about 2 hours. Wrap and then refrigerate until set, at least 2 hours, and up to overnight.

Combine cocoa and powdered monk fruit in a fine mesh strainer. Lift the ganache from the pan and cut into 30 pieces, cleaning the knife as you work for even cuts. Dust with the cocoa mixture, turning to coat all sides. Keep refrigerated until serving.