Line an 8x8 inch square pan with parchment paper, leaving an overhang on two sides for easy removal.

In a small saucepan over medium heat, cook 1 cup fresh or thawed frozen cranberries for 3 to 4 minutes, stirring occasionally, until they start to break down.

Add 1 cup granulated sugar and 1/2 cup heavy cream, stirring constantly until smooth.

Stir in 2 tablespoons butter and bring the mixture to a boil over medium-high heat, stirring frequently.

Attach a candy thermometer to the saucepan and cook, stirring occasionally, until the mixture reaches 238 to 242°F (soft-ball stage), about 8 to 10 minutes.

Remove from heat and stir in 1/4 teaspoon vanilla extract and a pinch of sea salt for about 30 seconds.

Pour the hot candy mixture into the prepared pan, spreading evenly with a spatula.

Let the candy cool at room temperature for at least 2 hours until firm.

Lift the set candy from the pan using the parchment overhang and cut into 24 pieces with a sharp knife, wiping the blade between cuts.

Roll each piece in 1/4 cup coarse sugar until fully coated, then set aside on parchment until ready to serve.