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