Preheat oven to 325°F.
Cook onion, garlic, cumin, salt, and oregano in 10 tablespoons butter (1-1/4 sticks) in a large heavy skillet over moderate heat, stirring, until onion is slightly softened, about 5 minutes.
Add cream and The Sauce and simmer, stirring, 1 minute.
Transfer mixture to a large bowl and toss with corn bread crumbs.
Toast pumpkin seeds in clean skillet over moderate heat, stirring constantly, until puffed, 5 to 8 minutes. (Seeds will pop as they puff.)
Remove from heat and stir into remaining 1/2 tablespoon butter. Salt to taste.
Add to corn bread mixture with cilantro and drizzle with broth, tossing to combine. (Adjust the amount of broth according to how moist you like your stuffing.)
Transfer stuffing to a buttered 3-quart shallow baking dish. Cover with foil and bake in middle of oven 30 minutes. Then uncover and bake until top is crisp and stuffing is heated through, about 30 minutes more.
Makes about 12 cups.
Stuffing can be assembled (but not baked), without pumpkin seeds, 1 day ahead and chilled, covered. Toss in pumpkin seeds and bring to room temperature before baking.