Roll prepared Bob's Red Mill Gluten Free Pie Crust between two pieces of parchment paper or heavy duty plastic wrap to a 10-inch circle. Remove the top layer of parchment or plastic and carefully invert dough into a 9-inch tart or quiche pan. Remove remaining sheet of parchment or plastic and press crust into pan, trimming the edges accordingly. Freeze at least 15 minutes.
Preheat oven to 350°F. Line the crust with parchment paper and fill with pie weights. Bake for 30 minutes. Remove the pie weights and parchment and continue to bake until light brown, about 15 additional minutes. Remove from oven and let cool while preparing the filling. Reduce the oven to 325°F.
To make the filling, heat olive oil in a sauté pan over medium-low heat. Add onions and cook until soft but not caramelized or brown, 5 - 10 minutes. Remove from heat.
Meanwhile, whisk together milk, cream, eggs and salt and pepper to taste.
In the cooled crust, layer 1/2 the onions and herbs, then pour over 1/2 the milk mixture and sprinkle with 1/2 the cheese. Repeat with the remaining filling ingredients.
Bake at 325°F until filling is set in the center, 60 - 90 minutes.
Let cool completely before serving. Serve at room temperature or chill and serve cold.