Preheat oven to 375 degrees F (190 degrees C).

Saute onion and garlic in oil in large saucepan until onion is translucent. Add mushrooms and spinach and continue cooking until mushrooms have released their juices and spinach has wilted. Continue cooking until liquid has evaporated. Remove from heat.

Beat eggs slightly in large bowl. Add ricotta and parmesan, sour cream, bread crumbs and parsley to eggs. Drain excess liquid from vegetables, then add to cheese mixture. Stir until well blended.

Brush some of melted butter on large baking sheet. Count out 6 phyllo leaves and carefully lift them up and lay flat on buttered baking sheet.

Spread filling over middle of leaves, leaving a 3 inch border all around. Brush edges with butter.

On top of the filling, lay down 2 leaves of phyllo at a time, brushing top leaf with butter each time. After 4 pairs, fold corners of all phyllo leaves up over filling, and brush with butter.

Lay down 2 more pairs of leaves, buttering top leaf of each pair. Tuck edges under torta, corners first, then sides. Sprinkle top with sesame or poppy seeds.

Bake at 375 degrees F (190 degrees C) for 50 minutes or until filling is set and phyllo is crisp and golden. Allow to rest 10 minutes before slicing.