Place a large skillet over medium-high heat with 1 tablespoon oil. Once the oil has heated, add the onion, seasoning well with salt and pepper. Sauté for 4-5 minutes, until onions soften. Add garlic and continue to cook for another minute. Stir in pumpkin puree, stock, jalapenos, chili powder, nutmeg and check if it needs more salt and pepper. Remove sauce from heat.