Preheat oven to 425°F (220°C). Line a large baking sheet with foil. Place whole poblano peppers on the baking sheet. Roast for 20-25 minutes, turning occasionally, until skins are blistered and charred.

Carefully transfer roasted poblanos to a bowl, cover tightly with plastic wrap or foil, and let steam for 10-15 minutes. This makes them easier to peel. Once cooled enough to handle, peel the skin from the chiles. Make a slit lengthwise down one side of each chile, carefully remove seeds and membranes, trying to keep the chiles intact. Set aside.

While chiles are steaming, heat 1 tbsp olive oil in a large skillet over medium-high heat. Add ground beef and cook, breaking it apart with a spoon, until browned. Drain any excess fat.

Add diced onion to the skillet and cook until softened, about 5 minutes. Stir in minced garlic, ground cumin, chili powder, dried oregano, salt, and black pepper. Cook for 1 minute until fragrant.

Stir in the undrained diced tomatoes and 1/2 cup beef broth. Bring to a simmer and cook for 5-7 minutes, allowing the sauce to thicken slightly. Remove from heat.

In a small mixing bowl, combine crushed tomatoes, 1/2 cup broth, salt, pepper, and optional sugar. Stir well.

Reduce oven temperature to 375°F (190°C). Lightly grease a 9x13 inch baking dish. Spread about half of the prepared tomato sauce evenly on the bottom of the baking dish.

Carefully stuff each peeled poblano chile with a generous amount of the ground beef filling. Arrange the stuffed chiles in a single layer over the sauce in the baking dish.

Pour the remaining tomato sauce over the chiles. Sprinkle evenly with the shredded Monterey Jack and Colby Jack cheeses.

Bake for 30-35 minutes, or until the sauce is bubbling and the cheese is melted and lightly golden.

Let the casserole rest for 5-10 minutes before serving. Garnish with fresh cilantro, sour cream, and sliced avocado, if desired. Serve with lime wedges.