6 large Ancho Chiles Whole, Dried
6 oz bacon, diced
1-1/4 lb onions, chopped (about 4 cups)
1 5-lb flat-cut (also called first-cut) beef brisket, cut into 2-1/2- to 3-in cubes
Coarse Kosher Salt
6 large garlic cloves, peeled
2 Tbsp Chile Powder, Hot or Medium
2 tsp Cumin Seeds
1 tsp Dried Mediterranean Oregano
1 tsp Ground Coriander
1-1/2 tsp Coarse Kosher Salt
1-1/2 10-oz cans fire-roasted diced tomatoes with green chiles (1-3/4 Cups)*
2 Tbsp Tomato Powder
1 12-oz bottle Mexican beer
1 7-oz can diced roasted green chiles*
1/2 Cup finely chopped fresh cilantro stems
4 Cups 1-1/2 to 2-in chunks seeded, peeled butternut squash (from one 3-1/2-lb squash)
Garnishes for chili:
Fresh cilantro leaves
Chopped red onion
Shredded Monterey Jack cheese
Warm corn and/or flour tortillas
Place Ancho chiles in medium heatproof bowl. Pour enough boiling water over to just cover. Soak until chiles soften, at least 30 min, and up to 4 hours.
Preheat oven to 350°F. Sauté bacon in heavy large oven-proof pot over medium-high heat until it begins to brown, about 6 min. Add chopped onions and saute, about 4 min. Reduce heat to medium; cover pot and continue cook until onions are browned and tender, about 5 more min. Season the cubed beef all over with coarse salt and pepper. Add to pot; stir ingredients to coat with fat, onions and seasonings. Set aside.
Drain soaked Ancho chiles, reserving soaking liquid. Place chiles in blender. Add 1 Cup of your soaking liquid, the garlic, chile powder, cumin seeds, oregano, coriander, and 1-1/2 tsp coarse salt; puree ingredients in the blender, adding more soaking liquid by 1/4 cupfuls if spice paste is very thick.
Pour blender spice puree over the cubed brisket in pot. Add tomatoes with juices, tomato powder, beer, green chiles, and cilantro stems. Stir to coat evenly.
Bring chili to simmer over medium-high heat. Cover pot and bake in 350F oven, 2 hours. Uncover and cook until beef is almost tender, about 1 additional hour. Add butternut squash to chili pot; stir to coat squash with chili sauce. Continue to roast, uncovered, until beef and squash are fork-tender. Add more soaking liquid, if needed, to keep meat moist and covered, about 45 min longer, before removing from oven.
Season chili to taste with salt and pepper. Tilt pot and spoon off any fat from surface of sauce, if desired.
[DO AHEAD: Can be made 2 days ahead. Cool 1 hour. Chill uncovered until cold, then cover and keep chilled.]
Set out garnishes in separate dishes.
If chili was made ahead of time, slowly re-warm chili over low heat. Ladle chili into bowls and serve.
*Available at many supermarkets and at specialty foods stores and Latin markets.