I trust you know about the T in "multumesc," which sounds like a German Z (ts). I have tried writing it once before in a KudoZ answer box, but the result was a garbled text. To avoid that, I am using a plain-vanilla T. The same goes for the other special characters.

Now, Romanians do not really name the meal when giving thanks to the host(ess). In other words, you don't say thank you for breakfast, lunch, or dinner. Immediately after the meal, the most common expression is "Multumesc pentru masa." The word "masa" literally means "table," but here it means the meal. That is the common expression before leaving the table.

If you are using the expression in a phone call the day after, then I would suggest something like "Multumesc pentru invitatia facuta si pentru bucatele gustoase oferite," which means, "Thank you for inviting us and for the delicious meal."

Fuad