1 tablespoon extra virgin olive oil
3/4 pound fresh tomatillos, husked, or 1 13-ounce can, drained
1 to 3 jalapeño or serrano chiles, roughly chopped
1 thick slice of onion, roughly chopped
2 garlic cloves, roughly chopped
Salt to taste
24 sprigs cilantro, plus chopped cilantro for garnish
1 tablespoon extra virgin olive oil or canola oil
1 1/2 cups vegetable or chicken stock
12 corn tortillas
1 1/4 pounds cod or snapper fillets
1 12-ounce bag baby spinach
2 ounces Mexican queso fresco or feta for sprinkling (optional)