In a food processor fitted with a chopping blade, pulse together 1[1/2] cups all-purpose flour, oregano, garlic powder, and [1/2] teaspoon salt five times.
Add cold butter and vegetable shortening, and pulse for 1 minute or until mixture resembles coarse meal.
Continue to pulse while adding ice water, about 1 minute. Test doughâ€”if it holds together when you pinch it, it doesn't need any more water. If it doesn't come together, add 3 more tablespoons cold water.
Remove dough from the food processor, put into a plastic bag, and form into a flat disc. Refrigerate for 30 minutes.
Preheat the oven to 400Ãƒâ€šÃ‚ÂºF. Flour a rolling pin and your counter.
Roll out dough to [1/4] inch thickness. Fit dough into an 8- or 9-inch tart pan. Using a fork, slightly puncture bottom of piecrust. Bake for 15 minutes. Remove from the oven, and set aside.
In a large skillet over medium heat, add extra-virgin olive oil, yellow onion, garlic, and asparagus, and saute for 5 minutes.
Add spinach, and cook for 3 or 4 more minutes. Remove from heat, and set aside.
In a large bowl, whisk together eggs, heavy cream, and ricotta cheese. Add remaining 1[1/2] teaspoons salt, Parmesan cheese, paprika, cayenne, black pepper, basil, parsley, and sun-dried tomatoes, and stir to combine.
Pour filling into piecrust, and bake for 40 minutes. Remove from the oven, and let rest for 20 minutes before serving warm.