Place the quartered onions, garlic, ginger, and jalapeños in the bowl of a food processor, pulse to a coarse puree, and set aside.
Place ½ cup of water next to your stovetop. Heat ¼ cup canola oil with the cardamom pods, cloves, chiles, cumin seeds, cinnamon, coriander seeds, and whole peppercorns in a large pot over medium-high heat until the cinnamon unfurls, 2 to 2½ minutes. Add the pureed onion mixture and salt and cook for 15 minutes, stirring often, scraping up the browned bits from the bottom of the pot and splashing the pot with water when the onions begin to stick.
Add the ground coriander, ground cumin, and turmeric and cook for 1 minute. Mix in 2 tablespoons of canola oil, the ground beef, oats, and 4 cups of water. Bring to a boil and reduce the heat to a simmer, cooking until the pot is fairly dry, 10 to 15 minutes. Add 3 more cups of water and bring back to a boil. Reduce the heat, cover, and simmer for 40 minutes, stirring every 10 minutes. Remove the lid and cook for 5 additional minutes. Serve with sliced onions, cilantro, and lime wedges.