In a small pan heat olive oil on high. Sauté the onion and leek 3 to 4 minutes until soft. Add the garlic and chicken stock and remove from heat.
Soak clay pot according to manufacturer’s directions. Pour stock mixture and all remaining ingredients, except rapini, into clay pot. Put into a cold oven. Turn oven on to 375° F. Bake for 35 minutes. Remove from oven and adjust seasoning. Sprinkle with blanched rapini.