Heat the olive oil in a large skillet over medium heat. Add the onions, mushrooms, ground beef, and garlic and saute for 6-8 minutes or until the ground beef is cooked through.

Add in the cumin, chili powder, salt, and pepper. Mix well and saute for 1-2 minutes. Remove from heat.

Lay the tortillas on a clean surface and divide the filling between the tortillas. Top with the cheddar cheese.

Roll the tortillas up tightly and place seam side down.

Wipe out the skillet used to make the filling. Add half the butter and melt it over medium heat.

Add half of the flautas to the pan and cook for 2-3 minutes per side or until they are crispy and golden brown. Remove from heat and repeat with remaining butter and flautas.

To make the lime crema combine the sour cream, lime juice, salt, and pepper. Mix well and thin with water. Serve over top of the flautas.