Why do I have lumps in my caramel? (NOT crystallized sugar.) There are a lot of caramel questions. Hopefully I'm not repeating anyone...
I've made caramel sauce several times with the recipe from Sally's Baking Addiction. (But using a different beginning procedure: Dissolve sugar in ~1/2 cup of water, not stirring. Put the lid on for a few minutes to clean the sides. After that it's the same.) For some reason, though, whenever I make it I end up with lots of tiny lumps suspended in my caramel. As I mention in the title, these lumps are not little sugar crystals. I've had my caramel crystallize before, and this is very different. They're soft, for one thing, and so I'm not sure what's happening.
At first I thought the little lumps were just air bubbles. That's what they look like. But they actually have some body to them. It's almost like I have tiny bits of cooked egg or something (which is obviously impossible.) They have a gelatinous quality. So my guess is that the cream is doing something weird? Flavor is good, thickness is good, everything is good except these stupid little lumps.
Does anyone know what's happening, and how I can make it stop...? I'm about to take an immersion blender to the mess and let God sort it out.
EDIT/UPDATE: So... I now have a theory that I tend to get my caramel so dark (more of a crimson/burnt sienna than an amber. Probably around 380F) that some of the dairy solids in the butter (maybe even the cream?) cook/coagulate as soon as I add it, leading to those gelatinous lumps. I haven't had the time (or a good reason) to try cooling my syrup with some water before I add the butter yet, but as I said in the original question, this definitely isn't sugar crystallization, and it's been a persistent problem. When my mom's made the recipe before, she didn't have the problem, but she's also terrified of burning her caramel and tends to add the butter much, much sooner.
I've noticed brown specks when I've made chewy caramels and toffee as well, so I'm wondering if cooked and browned dairy solids are my whole problem here.
I have failed many times to make that kind of recipes. They contain false direction, especially when it comes to melt the sugar.

Here is a quote which helps me. It's not accurate but you'll get the idea.


  The thing to do when you want caramel is to do nothing


In the recipe you provide, the author stirs the sugar while it cooks. That's a bad idea.

Sugar has a very complex crystal structure and it's not very stable when you heat it. Thus if you disturbed the crystals, you'll end up with lumps. During the last step (the one with the cream), it will emphasize those lumps.

So you need to refrain to stir during the melting step. If you have sugar sticking on the side of the pan, you could use a brush with some water. And again, do not stir.