If you haven't already toasted your cumin, do this first in a dry skillet over medium heat for about 1 minute until fragrant, then grind it fresh—this makes a real difference in the final flavor compared to pre-ground. While that cools slightly, measure out all your spices (chili powder, chipotle pepper, oregano, garlic powder, onion powder, salt, pepper, cayenne, and smoked paprika) into a small bowl and mix together. Shred your cheese if not already done, and arrange your tortillas and salsa within easy reach of your cooking station.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Once shimmering, add the ground beef and break it apart with a wooden spoon, cooking for 5-7 minutes until mostly browned. Add the spice mixture from Step 1 and stir constantly for about 1-2 minutes to bloom the spices and coat the meat evenly. I like using extra virgin olive oil because it adds a subtle richness that plays well with the smoky spices.
Stir in the tomato paste and beef stock, mixing well to deglaze the pan and create a cohesive, slightly saucy filling. Cook for 1-2 minutes, stirring occasionally, until the liquid reduces slightly and the flavors meld together. The tomato paste should darken and caramelize slightly against the pan—this deepens the flavor. Transfer the beef mixture to a bowl and let it cool while you prepare the tortillas.
Set your oven to 200°F to keep finished quesadillas warm while you cook the remaining ones. Lay out a tortilla and sprinkle about 1/3 of the shredded cheese on the left half, then add about 2-3 tablespoons of the beef filling from Step 3 on top of the cheese. Top with another 1/3 of the cheese, then fold the tortilla in half to create a semi-circle. Repeat this assembly process with all six tortillas, laying them on a plate as you finish each one.
Heat 2.5 tablespoons of vegetable oil in a large skillet over medium-low heat—you want medium-low rather than high heat so the tortilla crisps without burning before the cheese melts. Working in batches, carefully place 2 quesadillas at a time in the pan and cook for 2-3 minutes until the bottom is golden and crispy. Flip gently and cook for another 2-3 minutes on the second side until golden and the cheese begins oozing from the edges. Transfer each finished quesadilla to the warm oven on a baking sheet.
Once all quesadillas are cooked and warming in the oven, remove them and cut each one in half diagonally for easier serving. Arrange on a platter and serve immediately with salsa on the side or drizzled over the top. I recommend Pace Picante for a classic finish—the brightness cuts through the richness of the cheese and beef perfectly.