Why do I have lumps in my caramel? (NOT crystallized sugar.)
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.