I can't recall any Christmas or New Year's episodes of That Girl --but I sure recall the hilarious Thanksgiving ep, where she had to cook a turkey and a goose, and got the stuffings mixed up!
If I ever get things mixed up, I recall that:

"Sage! Sage! Sage in the Goose!...Oysters! Oysters! Oysters in the Turkey!"
:roller:


HAPPY NEW YEAR!!!!!!


:frosty: :rednose: :snowman3: peace: :mango :drink: :santa: :tree: :banana: :rock: :guitar: :drummer: party: :yippee:

The diamond-earrings-from-Tiffanys ep was a Valentine's Day ep

present: :loveya: :blush: :heart: :love:


She must've had a birthday ep, too.
:birthday: 22 • Paper Hats and Everything



And of course the Thanksgiving turkey/goose ep:

:turkey: :ducky:

35 • Thanksgiving Comes but Once a Year, Hopefully


And by gum, a Halloween/Election Day combined!:
62 • Secret Ballot pumpkin: patriot:

Don't recall an Easter ep
:bunny:


:cc: Christmas AND Hannukka were given a nod with: ep 15: Christmas and the Hard Luck Kid

New Years: 63 • Should All Our Old Acquaintance Be Forgot?

There was another Christmas episode in season 2. It's called "'Twas The Night Before Christmas, You're Under Arrest. "