Add sugar to water and whisk to dissolve sugar. Sprinkle yeast on top. Leave for 5 minutes until yeast gets foamy.
In the bowl of an electric mixer, combine salt, oil and 4 cups of the flour. Using dough hook attachment, give it a quick mix. Add proofed yeast and knead until the dough is very soft and stretchy, about 3 minutes. Add remaining flour as needed to form a soft, pliable and elastic dough.
Place in a lightly greased bowl. Cover with plastic wrap and a kitchen towel. Leave to rise until doubled in size, about 1 hour.
Spray a baking dish with non stick spray. With floured fingertips press dough into baking dish, making sure dough goes up the sides of the dish.. You can use a 9 x 11 baking dish or use different decorative shaped baking dishes as I did. Cover with a kitchen towel and leave to rise for 45 minutes.
Preheat oven to 425 F.
Spread ricotta filling on top. Using a pastry brush, brush filling to the edges.
Bake for 25 - 30 minutes until there is a golden browned crust.
Brush the edges with melted butter and sprinkle liberally with pistacchio topping.