To a small saucepan over medium-high heat, add the apple cider and cinnamon. Cook for 18-20 minutes until reduced to about 1/4 cup. Set aside.

In a separate medium heavy-bottomed saucepan, add the sugar. Spread evenly and cook over medium-low heat without stirring until melting begins around the edges, then gently tilt and stir until melted and golden.

Cook the sugar until deep amber, about 5-10 minutes, stirring gently.

Reduce heat to low and carefully add butter, stirring until melted.

Gradually add the warm heavy cream while stirring. The mixture will bubble.

Stir in the reduced apple cider and vanilla until combined. Add a pinch of salt and stir.

Continue cooking on low until smooth, about 5-10 minutes.

Remove from heat and let cool to thicken. Serve warm or cold.