Step 1

Crank the oven to 325ºF with a rack in the middle. Line a half sheet pan with parchment paper.

Step 2

Whisk the ketchup, tomato paste, chipotles, adobo sauce, cocoa powder, brown sugar, and garlic powder together in a small bowl. This is your chipotle glaze. Measure out about 1/4 cup for serving, then reserve the remaining 3/4 cup for brushing on the meatloaf.

Step 3

Load the work bowl of your food processor with the croutons, chili powder, thyme, black pepper, and cayenne (if desired) and pulse to coarse crumbs. Transfer the mixture to a large mixing bowl.

Step 4

Add the onion, bell pepper, carrot, and garlic to the food processor bowl and pulse until finely chopped but not pureed, scraping the bowl with a rubber spatula about halfway through the process, about 8 one-second pulses. Transfer to the bowl with the breadcrumbs.

Step 5

In two batches, pulse the chuck and sirloin until it resembles a coarse, medium grind, 10 to 15 one-second pulses. Add the meat to the bowl with the crouton and vegetable mixture, along with the salt, and mix with your hands to combine. Quickly work in the egg.

Step 6

Pack the meat mixture into a 9-by-5-by-3-inch loaf pan. Run an offset spatula along the edge of the meatloaf, then turn the meatloaf out onto the prepared sheet pan. Remove the loaf pan. Insert a temperature probe into the top of the loaf at a 45-degree angle, being careful not to push the tip through to the bottom of the pan. Set the thermometer alarm for 155°F and place the pan on the middle rack in the oven.

Step 7

After the meatloaf has been cooking for 15 minutes, slide it out on the rack and quickly brush with the 3/4 cup of the glaze. Return to the oven and cook until the probe alarm sounds at 155°F, 45 minutes to 1 hour longer. Transfer the meatloaf to a platter and let rest for at least 20 minutes before slicing and serving with the remaining glaze for dipping.