In a large pot over high heat, heat the oil and butter. Working in 2 batches, cook the beef until browned on all sides, 1 to 2 minutes. Add the cumin, chili powder, garlic and some salt and pepper and cook for 1 to 2 minutes to deepen the flavors.
Add the beef broth and chipotle peppers with adobo sauce, stir and bring to a boil. Reduce the heat to low, cover and simmer until the meat is fall-apart tender and the liquid is thick, 2 1/2 to 3 hours. Check occasionally and add more beef broth if the sauce becomes too thick or dry.
Serve immediately and garnish with the green onions, or allow to cool, cover with foil and refrigerate. To reheat, cook at 350 degrees F for 30 minutes. Garnish with the green onions before serving.
If serving with the Pimiento Cheese and Bacon Grits, spoon the hot stew over the warm grits in a 9-by-13-inch baking dish and serve immediately or cover with foil and refrigerate. To reheat, cook at 350 degrees F for 30 minutes. Garnish with the green onions before serving.
Pimiento Cheese and Bacon Grits:
In a skillet over medium heat, cook the bacon until crisp, 10 to 12 minutes. Remove it to a paper towel-lined plate.
Meanwhile, bring 4 cups of water to a boil in a medium saucepan. Whisk in the grits and salt. Reduce the heat to low, cover and cook, stirring occasionally, for 30 minutes.
Stir in the half-and-half and cook until the grits are tender and creamy, about 20 more minutes.
Add the pimientos, cream cheese, Cheddar and mustard and stir until melted together and combined. Chop the bacon into small pieces and add to the grits. Stir in the pepper and serve.