Toast the pepitas in a skillet.
Stir frequently. Be careful not to burn.
Once they start popping, remove immediately.
Roast tomatillos, ½ onion, 5 garlic cloves, and serrano peppers.
You can do this on the stove or under the broiler until the skin on everything is charred.
Place the pepitas and the roasted ingredients in a blender.
Blend until smooth.
In a large stock pot, add the chicken, water, bay leaf, salt, ½ onion, and 1 garlic clove.
Place a lid on the pot and cook thoroughly.
In a separate pot, heat the oil and add the sauce.
Bring to a simmer.
Add the cooked chicken.
Bring to a simmer again.
Let cook for 10 minutes.
Serve with rice.