Preheat your oven to 350° F (175° C).
In a large bowl, mash both ripe avocados. Add the flour and Greek yogurt, and mix until combined. A sticky dough should form.
Cut a piece of parchment paper that's a little bigger than your sheet pan, and place on the counter or a flat surface.
Transfer the dough to the parchment paper. Using your hand or a rolling pin, press and spread the dough across the sheet pan.
Lay a piece of wax paper, or another sheet of parchment paper, on top of the dough. Using a rolling pin, spread the dough thinly (tortilla thin). You may need to split dough in half and bake in two batches.
When your dough is spread evenly across the whole piece of parchment paper in one thin layer, remove the top piece of wax paper or parchment paper. Carefully transfer the parchment paper and dough to a sheet pan.
Bake for 7-15 minutes, or until the center is firm and the edges are golden brown. Bake time can vary depending on the thickness of your tortilla.
Remove the sheet pan from the oven and let the tortilla cool completely. Cut into squares or desired shape. Enjoy!
