In a medium saucepan, whisk together the cocoa powder, granulated sugar, brown sugar, and a pinch of salt until fully combined.

Add the heavy cream and unsalted butter.

Stir constantly over medium heat, allowing the mixture to come to a low simmer.

Continue stirring for 3–5 minutes until the sauce becomes smooth, thick, and glossy.

Remove from heat and stir in the vanilla extract.

Set aside to cool slightly — it should still be warm when served.

Tip: The sauce can be made ahead and refrigerated for up to a week. Just reheat gently before use.

2. Build Your Sundae
Assembling your sundae should be an experience of joy. Here’s how we do it:

Scoop three generous balls of vanilla ice cream into a tall sundae glass or dessert bowl.

Pour warm hot fudge sauce over the top, allowing it to cascade down the sides of the ice cream.

Add a generous swirl of whipped cream.

Top it all off with a glistening maraschino or fresh cherry.