Preheat oven to 375 degrees Fahrenheit. Prepared dough should be rolled out and placed in a 9- or 10-inch pie pan as a crust. Some prepared pie shells can be purchased already in a tin.

In a skillet over medium-high heat, add oil. Add onion and salt and saute, 3 minutes. Add pepper, nutmeg, spinach, and basil, and cook for 5 minutes until spinach is wilted. Remove from heat.

In a large bowl, whisk together ricotta and eggs. Mix in cheese and onion spinach mixture and mix well. Pour mixture into pie crust and bake till firm and golden brown, 45 minutes.

Serve warm or at room temperature.