Onion Prosciutto Tart

I had this at a little fancy place in little ol' Omaha. This is the best I can do to duplicate it. But it doesn't matter if it is spot on, it is still the best thing since.. I don't know what. My mom usually has all the ingredients ready for me to make it when I come to visit her. She makes me make a bunch of them, and she pulls them out of the freezer when she has guests!

• Ready In: 2 hrs
• Serves: 8

Ingredients

• 1  pie shell
• 3  large sweet onions
• 1⁄4 cup butter
• 1⁄2 teaspoon salt
• 1  teaspoon flour
• 2  tablespoons fresh thyme or 2  teaspoons dried thyme
• 1⁄4 lb prosciutto, chopped
• 1⁄2 cup heavy whipping cream

Directions

1. slice onions into round disks. then slice the disk into 4 equal parts. So that you have some small, and some that are longer.
2. Melt butter on Medium. Add onions, they should not sizzle! you need to sweat them to get all of the wonderful sugars going. This may take awhile.
3. Once the onions have reduced themselves by half, turn the heat up to Medium High, and add salt.
4. When the onions look shinny, and start to turn golden. Stir in flour, thyme and prosciutto, stir and cook for 5 minutes.
5. Pour in 1/4 cup of the whipping cream. Stir to coat. It should be the consistency of mac and cheese. If it is too dry add more cream. But remember, if you add too much, your tart will be runny.
6. Pour onion mixture into prepared pie shell.
7. Bake at 350°F for 45 min to an hour. Be sure to watch the crust so it doesn't burn. the crust should be golden brown, and the top should look caramelized.