I asked my professor to write a letter of recommendation for me. She said she would in general be happy to do that. I am quite self-conscious and worried, I would like to send an email back and say thanks, but I don't want to sound overly grateful. Since English isn't my first language, I would like to ask you how you would write something like this. Or: Would you maybe not write back at all, since the professor's email box must be super busy and sending a simple thank you email might annoy them more than anything else?
I'm so not sure about this, thanks a lot!