In a heavy-bottomed saucepan over medium heat, spread the sugar evenly.
Let it melt without stirring (swirl the pan occasionally for even browning).
Once melted, cook until the sugar turns a deep amber color (~5–7 minutes).
Do not walk away—it can burn quickly!
Carefully whisk in the butter (mixture will bubble vigorously).
Stir until fully melted and combined.
Slowly drizzle in the warm cream while whisking constantly.
Simmer for 1–2 minutes until smooth.
Remove from heat; stir in vanilla and salt (if using).
Let cool slightly before transferring to a jar.
Storage: Keeps for 2 weeks refrigerated. Reheat gently before use.
