Place the cooked and drained tomatillos in a
blender with the
pumpkin seeds,
sesame seeds, Serrano peppers, garlic, onion, romaine lettuce leaves,
Hoja Santa leaves, cilantro leaves, spices, and 1 cup of water or
chicken broth. Process until you have a very smooth sauce. Depending on your
blender, you may need to work in batches.