Here is the full list of all 28 Katy & Bob: Cake Café achievements.
Wedding Bakery world complete
All objectives completed on 60 levels
60 levels completed on Expert
All artifacts purchased
City Bakery world complete
All objectives completed on 40 levels
40 levels completed on Expert
1000 guests served
200 drinks made
Fireworks used 50 times
Fireworks used 25 times
Home Bakery world complete
20 levels completed on Expert
All objectives completed on 20 levels
500 guests served
100 drinks made
250 cakes sold
Fireworks used 1 times
200 cake bases made
50 drinks made
10000 gathered in total
100 cakes sold
100 cake bases made
5000 gathered in total
100 guests served
50 cake bases made
25 cakes sold
100 gathered in total