First, preheat the oven to 400ºF.
In a large skillet, brown the ground beef and drain any excess fat.
Add the chili powder, cumin, garlic powder, oregano, and paprika, plus a tablespoon or two of water to help coat the ground beef with the spices.
In a medium saucepan, begin preparing the cheese sauce by melting the butter over medium heat.
Slowly add the heavy cream, whisking gently to combine,
Add 2 cups of the shredded cheddar cheese, whisking until the cheese has melted and the mixture is smooth.
Grease a 9x13-inch baking dish and begin layering the taco lasagna. Start with a single layer of flour tortillas, then top with about 1/3 of the ground beef.
Top the ground beef with 1/3 of the cheese sauce and then sprinkle some of the pico de gallo on top of the cheese sauce.
Place another layer of flour tortillas on top of the pico and repeat the layers until you reach the top of the pan (or run out of ingredients).
Top with the remaining cup of shredded cheese,
Bake for 20-25 minutes, or until the cheese on top is hot and bubbling.
Serve with sour cream and guacamole, if desired.