spaghetti

Hi y'all, I'm really sorry if this has been asked before. I tried searching for thank you note threads but couldn't find an answer to my exact question (maybe my search wasn't thorough enough). When thanking a teacher for writing a letter of recommendation, should I send an email or a card? I think the card would be more personal, but I would want to thank him/her immediately after seeing the letter has been submitted, and the e-mail would be faster than mailing a card. Would it be overkill to send a thank you e-mail and a physical card? Also, do I send the card/email right after he/she submits the letter of recommendation or do I send it after acceptance/rejection? Thank you for your help, gradcafe!