Preheat the oven to 350°F and grease a standard casserole dish with butter.

In a large bowl, mash the feta and ricotta with a potato masher or fork. Stir in the thyme, oregano, black pepper, and salt.

Place two sheets of fillo in the dish and brush them with butter. The sheets should hang out the edge of the dish. Take two more sheets and repeat the process, hanging the sheets over the final two edges. Make sure every bit of the fillo has butter.

Divide the rest of the fillo into two piles and cover with a damp towel to keep moist. Take the first pile, brush each piece of fillo with butter, gently crumple and place in the dish. The crumpled fillo should be evenly spread out. Spread the cheese mixture over the fillo base. Use the second pile, except for two sheets, to cover the cheese mixture using the same technique of buttering and gently crumpling. Butter and place the final two sheets over the top. Gently roll down the edges hanging over the sides to create a neat border.

Use a razor or sharp knife to score the top of the pie. Pour the milk evenly over the top and garnish with sesame seeds. Cover the dish with aluminum foil and let the pie sit for a few minutes before placing in the oven. Bake for 15 minutes, remove the foil and bake for an additional 20-25 minutes or until golden brown. 

Best served warm. To reheat, place in the oven for 10 minutes at 350°F. Enjoy!