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