Here is the full list of all 21 Delicious - there are Emily's Christmas Carol achievements.
Use every product in every restaurant at least once
Collect all other achievements
Unlock all product upgrades
Finish all events and challenges
Serve 500 chocolate related products
Walk 1000 miles
Find the two turtle doves in the game and reunite them
Finish every level with 3 stars
Serve 400 customers quickly
Find all mice
Buy all the secret gifts and use them
Finish Santa’s Home
Buy all shop items
Finish Mary's Toy Shop
Make 250 combos
Finish The Reindeer Farm
Pick up all the nuts the squirrel leaves behind
Finish the Miracle Express
Finish George's Train Station
Restock items 350 times
Finish Emily's Snow Garden