Very trivial, I know (first world problem)
I make all 3 kids 2 rounds of toast, if toast is what they want for breakfast.
If nearly 7 yo wants more, AIBU to say he can have up to 2 more slices, but only if he makes it himself? Same rule would apply to his older sister, but as she never wants more than 2 slices he feels life is terribly unfair.
He is fully capable of making toast, his concern is that he makes holes when buttering it :o