1/4 cup raw pumpkin seeds 2 teaspoons cumin seeds 1 tablespoon extra-virgin olive oil 2 red onions, thinly sliced 4 cloves garlic, minced 2 tablespoons tomato paste 1 teaspoon cracked black peppercorns 1 teaspoon dried oregano 1/2 teaspoon sea salt 1/4 teaspoon cinnamon 2 cups chopped cilantro leaves and some stems, plus finely chopped cilantro, for garnish 1 tablespoon grated lemon zest, plus grated lemon zest, for garnish 2 tablespoons freshly squeezed lemon juice 1 cup chicken stock 3 pounds skinless bone-in chicken thighs, about 12 thighs 1 to 2 jalapeņo peppers, minced Finely chopped green onion, for garnish Salsa, optional

In a dry skillet over medium heat, toast the pumpkin and cumin seeds, until the pumpkin seeds are popping and the cumin has released its flavor. Transfer to a mortar or spice grinder and grind. Set aside.
In the same skillet, heat the oil over medium heat. Add the onions and cook, stirring, until softened, about 3 minutes. Add the garlic, tomato paste, peppercorns, oregano, salt, cinnamon, and cilantro. Cook, stirring, for 1 minute. Transfer contents of the pan to a food processor. Add the lemon zest and juice, chicken stock, and reserved pumpkin and cumin seeds. Process until smooth.
Arrange the chicken evenly over the bottom of the slow cooker stoneware. Pour the sauce over the chicken. Cover and cook on low for 6 hours or on high for 3 hours, until the juices run clear when the chicken is pierced with a fork. Stir in the jalapeņo pepper to taste. When ready to serve, garnish with the cilantro, green onion, lemon zest, and salsa, if you wish.