Line an 8x8 dish with parchment paper or aluminum foil. Lightly spray it with non-stick spray and set aside.

Add the dark chocolate chips, semi-sweet chocolate chips, sweetened condensed milk, butter, and a pinch of fine sea salt to a medium-sized non-stick saucepan and heat over medium-low heat.

Stir to combine and continue stirring, almost constantly, until all the chocolate is melted and the fudge starts to come together. Remove the fudge from the heat and stir in the peppermint and vanilla extracts.

Transfer the fudge to the prepared baking dish and use a spatula to spread it out evenly. Sprinkle the crushed peppermint candies over the top of the fudge and lightly press into the fudge a bit. Let the fudge cool to room temperature and then refrigerate it until it's cooled completely (about 2 hours).

When the fudge is completely chilled, cut it into squares and serve at room temperature.