When it comes to the toppings, anything goes. You'll need about 1/2 cup for each one. For finer ingredients like poppy seeds or dried herbs, you'll need slightly less — about 1/4 to 1/3 cup.
Need some inspiration? Here's what we used in our version:
1/2 cup shredded cheddar cheese + 1 tablespoon taco seasoning
1/2 cup grated Parmesan cheese + 1 tablespoon each dried parsley, dried oregano and minced garlic
1/4 cup chopped ham + 1/4 cup shredded cheddar cheese
1/2 cup dried cranberries + 1 tablespoon fresh rosemary
1/4 chopped olives + 1/4 cup crumbled feta + 1 tablespoon fresh dill
1/4 cup everything bagel spice (or poppy seeds)
Feel free to use whatever spices, herbs and fixings you have on hand for toppings.