His smile grows, taking on a distinct sense of delighted accomplishment; it's a job well done, and he's done it right, done his duty. He's happy about this.

"Yes, ma'am," he says, recognition lighting his eyes. "That's what it said on the note. Sorry, I just had to make sure. I'm Captain Steve Rogers--" and here he offers his right hand, still holding the cauldron by the other one-- "and if you need me to carry this someplace for you, I don't mind at all."