Step 1

In a large skillet over medium-high heat, heat 2 tablespoons of canola oil. Once the oil is hot, add in the beef roast, one section at a time, and brown all over, about 2 minutes per side. Transfer to the slow cooker and repeat until all of the beef has been browned.

Step 2

Add the onion, jalapeños, poblanos, garlic, crushed tomatoes, salt, pepper, 1/2 cup of the chili powder, and the cumin to the slow cooker. Set to low and cook for 10-12 hours, or until the beef shreds easily.

Step 3

Remove the beef from the slow cooker and shred with two forks. Skim off excess fat floating atop the liquids in the slow cooker, if there are any, and dispose of them. Set aside.

Step 4

In a large pot over medium heat, whisk together the remaining 1/3 cup of canola oil and the flour until it turns a light tan color. Whisk in the remaining 1/4 cup chili powder.

Step 5

Slowly whisk the reserved liquids from the slow cooker into the flour mixture. As it heats, the mixture will thicken up. If it gets too thick, add a bit of water to thin to your desired consistency.

Step 6

Remove a cup of the sauce for smothering the burritos and set aside. Mix the beef into the remaining sauce mixture and stir to mix well.

Step 7

Preheat the oven to 375° F. Spray a baking dish with cooking spray and set aside.

Step 8

Place a mound of the filling in the very center of each tortilla. Fold the top and bottom of the tortillas over the filling, and then fold the left side of the tortilla over the filling and tuck it under. Roll the entire burrito tightly to the right until the burrito is formed. Transfer the burrito, seam side down, to the baking dish. Repeat until the baking dish is full. You can save any additional filling and burrito ingredients for leftovers, if desired, or you can make them all at once.

Step 9

Drizzle the burritos with reserved sauce and top with cheddar cheese, as desired. Bake for 10-15 minutes, or until the cheese is melted and bubbly.

Step 10

Top the burritos with sour cream, chopped tomato, and cilantro, to serve.