The food I make isn't something I just came up with, I used the recipe in the Frasier/Eckroate book The Natural Cat. My vet said it was also suitable for the dog.
The rule of thumb is 1/2 tsp powdered egg shell to one pound of meat. If the calcium isn't added you can end up with too high a phosphorus ratio in the food and end up with kidney issues.
Broccoli is good, but too much can cause thyroid issues... vets get little or no training in pet nutrition in school, I long ago quit taking any kind of nutritional advice from my vet. The training they receive is given by vets hired and trained by Hills and/or Purina.