Prepare the Dish: Pour 3 tablespoons of oil into a 9 x 13-inch baking dish. Use a brush to coat the entire surface evenly. Place the dish in the oven and preheat to 420°F (215°C). The oil will heat up, creating a crispy crust for the cornbread.

Mix the Wet Ingredients: In a large mixing bowl, whisk the eggs until frothy. Add the milk and ⅔ cup oil, whisking until smooth.

Combine the Dry Ingredients: Gradually add the cornmeal and flour to the wet mixture, stirring until just combined. Mix in the baking powder, salt, and crumbled feta cheese, ensuring the batter is smooth and lump-free. Let the batter rest for 5 minutes.

Assemble and Bake: Carefully remove the hot baking dish from the oven. Give the batter a final stir, then pour it into the dish, spreading it evenly. Sprinkle generously with sesame seeds. Bake for 20-22 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean.

Cool and Serve: Allow the cornbread to cool slightly before cutting into squares. Serve warm with a dollop of sour cream for a deliciously savory treat!