Here is the full list of all 10 Extra Cream achievements.
Reach level 2!
Complete an order just as the customer is leaving
Reach level 5!
Reach level 10!
Complete an order worth $100 or more
Upgrade the combine speed trait to the max
Upgrade your shop
Upgrade your shop to the max
Watch the ending cutscene. Congratulations!
Use either of your abilities a total of 50 times