For base

1. Heat oven to 400 degrees. Grease a 9-inch tart pan with removable bottom and set aside.
2. Make half of the Simple Mills bread mix into a pie crust and place in tart pan, making sure to press crust about 1 ½-2 inches up the sides.
3. Bake for 15 minutes and set aside while making filling.

For filling

1. heat avocado oil in a skillet over medium-high heat and sauté onions for 5 minutes or until starting to soften.
2. Add mushrooms and cook another 10 minutes or until they have released all of their juices and are starting to brown.
3. Remove from heat and mix in chestnuts, thyme, and salt and pepper. Pour into pie crust and bake another 10 minutes, or until warmed through.
4. Allow to cool, slightly before serving. Tart is best served at room temperature or slightly warm.