Cook the Beef & Bean Filling:
In a large skillet over medium-high heat, add the ground beef and chopped onion. Cook, breaking up the meat, until the beef is fully browned, about 5-7 minutes. Drain off any excess fat. Stir in the minced garlic and cook for 1 minute more until fragrant.

Simmer the Sauce:
Add the chili powder, cumin, and oregano, stirring constantly for about 30 seconds to toast the spices. Pour in the tomato sauce, diced green chilis, and chopped jalapenos. Mix in the refried beans until everything is well combined. Bring the mixture to a simmer, then reduce the heat to low. Let it cook for 10-15 minutes, stirring occasionally, until the filling has thickened. Season with salt and pepper to your liking.

Cool the Filling:
Transfer the filling to a bowl or sheet pan and let it cool for at least 15-20 minutes. A cooled filling is crucial to prevent the tortillas from becoming soggy or tearing during assembly and frying.

Assemble the Chimichangas:
Warm the tortillas slightly to make them more pliable. Lay a tortilla flat and spoon about ½ cup of the beef filling in a line across the lower third. Sprinkle with a generous amount of shredded cheese. Fold the bottom edge up and over the filling, tucking it in tightly. Fold in the left and right sides, then continue rolling into a secure, tight packet.

Fry to Golden Perfection:
In a large, deep pot, pour in about 2 inches of oil. Heat the oil over medium-high heat to 365°F (185°C). Using tongs, carefully place 2-3 chimichangas seam-side down in the hot oil. Fry for 2-3 minutes per side, until deep golden brown and crispy. Do not overcrowd the pan.

Drain and Serve:
Remove the chimichangas from the oil and place them on a wire rack to drain any excess oil. Serve immediately.