Preheat oven at 400 degrees F (200 C).

Chop the sweet potatoes in small cubes about ½ inch cubes. Place in bowl and drizzle 1 ½ tablespoon olive oil, mix until all pieces are coated with the oil. Spread in a pan and roast for 20-25 minutes. Remove and set aside, lower oven temperature to 350 F (180 C).

In the meantime sauté the onion in 2 teaspoons of olive oil until translucent.

In a large bowl mix the crumbled feta, eggs, milk, 1 tablespoon herbs de provence , 1 teaspoon salt, freshly ground pepper, 1 ½ tablespoon olive oil. Add the onion (let it cool a few minutes before adding) and the sweet potato cubes. Mix gently and set aside.

Brush a 10 inch tart pan with olive oil. Place 6 sheets of phyllo in the pan, brushing each layer with olive oil. Cut off the leftover pieces hanging over the sides of the pan. * If you are using homemade phyllo see notes.

Empty the sweet potato mixture in the pan, spreading it evenly with a spatula. Sprinkle with parmesan.

Cover the tart loosely with aluminum foil and bake for about 20 minutes. Remove aluminum foil and bake for another 20-25 minutes.

Remove from oven and let it cool before slicing.