Preheat the oven to 400ºF and line a baking sheet with parchment paper. Set aside.
Heat the ground beef in a large skillet over medium/high heat for 2-3 minutes, breaking the beef up into small pieces.
Add the taco seasoning to the beef and cook until the ground beef is no longer pink. Remove from heat.
Add the shredded cheese and Greek yogurt to the beef and stir to combine.
Lay the 9 tortillas out on a clean, flat surface. Distribute the refried beans evenly between the tortillas. Top with the ground beef.
Fold each tortilla in half and transfer to the greased baking sheet.
Bake the tacos for 12-15 minutes, flipping halfway through so both sides of the tortillas become golden brown. Remove from the oven.
While the tacos are baking, make the avocado crema by adding the avocado meat, lime juice, cilantro, and a pinch of salt to a blender or food processor. Blend until smooth.
Top each taco with crema and enjoy immediately.