Dear Grandpa,

Thank you so much for the yummy sticks you gave me to help my celebrate my confirmation. It was a special day for me, and your gracious gift made it even better because you know I just love those sticks you bring!

Thanks again,

Love, Miss Hoppy

*****

Really the most important part is that you write a note expressing thanks. I'm sure you "get" that you can just substitute the proper info for the pink parts in above sample - that'll give you a starting point!