What is the difference between hot fudge and chocolate syrup?
Hot fudge is thicker, richer, and more dairy-forward, usually made with butter and cream (and often cocoa plus chocolate). Chocolate syrup is typically thinner and sweeter, and it is meant to pour cold.
How do I fix grainy hot fudge sauce?
Graininess usually means the sugar did not fully dissolve or the sauce was cooked too aggressively. Keep it at a gentle simmer (not a hard boil) and whisk regularly, scraping the corners of the pan. If it is already grainy, warm it gently over low heat and whisk until the sauce is fully smooth again. A tablespoon of cream can help loosen things, but the real fix is giving the sugar time to dissolve. If you want extra insurance next time, use the optional corn syrup or honey.
Why did my sauce separate or look oily?
That is usually from overheating after the chocolate goes in. Pull it off the heat, whisk like you mean it, and add a splash of warm cream. If needed, return to very low heat just long enough to smooth it out.
Can I use milk instead of cream?
You can, but it will be thinner and less fudgy. If you only have milk, use whole milk and expect a looser pour. Let it simmer 1 to 2 minutes longer to thicken, and consider adding 1 extra tablespoon of butter for a little more richness.
Can I make it dairy-free?
Yes. Use full-fat canned coconut milk in place of cream and a plant-based butter. The flavor will lean slightly coconut, which is honestly pretty great on brownies.