To make a spanokopita, you'll first need to prepare the filling. First, preheat the oven to 375 degrees F (190 degrees C). Then, slice the avocado in half lengthwise and scoop out the pita bread slices. Place the sliced avocado on top of the tortillas. Top with shredded cheese and sour cream. Bake for 15 to 20 minutes or until the cheese is melted. Serve warm.