In a large skillet over medium heat, brown the ground beef along with a finely diced onion for 5-7 minutes, until browned. Drain excess grease, then stir in minced garlic, taco seasoning, and salsa. Let simmer for an additional 5 minutes until thickened and fragrant.

Lay out your large flour tortillas on a flat surface. Spread a layer of refried beans (if using) across each tortilla, then add a scoop of the beef mixture and a sprinkle of shredded cheese. Fold in the sides and tightly roll them up.

If frying, heat vegetable oil in a deep skillet or fryer to 350°F (175°C). For baking, preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Carefully place the chimichangas seam-side down in the hot oil. Fry for 3-5 minutes on each side until golden brown and crispy. If baking, arrange on the prepared baking sheet, brush lightly with oil, and bake for about 20-25 minutes until crisp.

Once cooked, remove chimichangas from heat and allow to cool for a minute or two. Serve warm with toppings like sour cream, guacamole, or additional salsa.