Heat a medium saucepan over medium heat. Sprinkle in the sugar and let it melt, stirring occasionally until amber and bubbly. Don’t wander away—the sugar burns faster than your last fantasy football team.
Once melted, add the butter. Stir until it’s fully melted and incorporated. It’ll bubble like a mini lava lamp—embrace the glow.
Slowly whisk in the heavy cream. The mixture will bubble up, calm down, then thicken. If it looks a little clumpy, keep whisking until silky smooth.
Stir in the salt and vanilla (if using). Taste a tiny bit—adjust salt if you want a bolder finish.
For extra thickness, whisk in a pinch of xanthan gum or arrowroot powder. Add just a little at a time until you reach your preferred consistency. Don’t overdo it—you’re aiming for glossy, not gummy.
Remove from heat. Let cool a few minutes before serving. It will continue to thicken as it rests. If it’s too thick later, warm gently and whisk again.