All the grandchildren wanted others and Grandpa ate three of them

Meaning:
“This sentence looks like a riddle or a joke that plays with words.”
Possible interpretation 1: Secondaries and their theft
Meaning of the word “secondaries”:
It can refer to other portions of food, such as other pieces of cake, other portions of soup, or other food that family members still want.
Situation:
The grandchildren wanted their “secondaries” (another portion of food).
However, the grandfather took three of them – that is, he ate three of their portions.
Conclusion:

 

the recipe on the next page