- Place the rack in the lowest position of the oven. Top with a pizza stone or an upside-down baking sheet. Preheat the oven to 250 °C (500 °F).
- Place the pizza crusts, frozen or slightly thawed on two separate sheets of parchment paper. Spread with the cilantro purée and sour cream. Top with the chicken, onion, and cheese.
- Place the pizza with the parchment paper on the hot baking sheet. Bake for about 8 minutes or until the crust is golden brown. Bake, one at a time, if the baking sheet or stone seems too small. Sprinkle with cilantro. Cut into wedges and serve.
For a slightly softer crust, allow the frozen crust to come to room temperature while preparing the ingredients, about 15 minutes. For an added kick, add thin slices of jalapeno. Cilantro, like many herbs, comes puréed in tube form in the fruit and vegetable section of most grocery stores.