1. Start with the onions first. It does take about 30 minutes to caramelize onions which you can do while you’re doing the other prep. Peel onion, cut in half, then slice into thin slices. Cook in a pan, medium heat, with butter (1 tablespoon) and olive oil (1 tablespoon) – more if needed. Add a little salt here but not too much. While you’re doing the other prep, stir the onions here and there making sure not to let them burn. If heat is too high, turn it down a bit. Set aside when done.
2. Peel and cut sweet potato into cubes. Put in a small pot with water. Let them cook until just barely softened (about 10-15 minutes). Strain them in a colander and run cold water over them to stop the cooking process. While they are cooking, you should continue stirring the onions and doing the other prep.
3. IF YOU ARE MAKING THE HOMEMADE CRUST MAKE IT NOW, WRAP, AND STICK IN THE FREEZER FOR 10 MINUTES. IF YOU’RE USING STORE-BOUGHT CRUST PROCEED WITH RECIPE. **RECIPE FOR DOUGH IS AT THE BOTTOM**
4. Shred the parmesan cheese. I almost always have a block of parmesan cheese on hand so I like to shred it fresh. You can also use the store-bought already-shredded kind to save a little time.
5. Measure out the bleu cheese. Set aside.
6. Beat 6 large eggs in a bowl until combined, then add heavy cream (or milk) and salt. Beat together until cream is incorporated.  Set aside.
7. If you’re using the homemade dough – follow the instructions below for that then add ingredients in step 8 below.
8. If you’re using store bought dough, remove from the refrigerator and it’s time to assemble the quiche. First, place the cooled-down sweet potatoes in the bottom, spread the caramelized onions across the sweet potatoes using a fork, add parmesan, add bleu cheese. Whisk eggs one final time and pour evenly into the pie crust.
9. Cover the crust with a silicone crust protector OR aluminum foil if you don’t have that. Bake in a preheated oven at 400 degrees for 15 minutes, then turn heat down for another 35-40 minutes until cooked through. Use a toothpick to check doneness.

For the homemade dough if you're going that route:

1. Cut your cold butter into cubes – makes it easier for mixing the dough. 
2. Put flour in a large bowl. Add your salt and sugar and mix with a fork.
3. Add butter cubes and mix with a pastry cutter if you have one. You can use your hands too if you don’t have a pastry cutter – or two forks to help break down the butter a bit. Work the flour and butter together until it has a slight crumbly texture and the butter is down to approximately pea size.
4. When it gets to that crumbly point, you’ll add the very cold water, 2 tablespoons to start then a little more if needed. I usually pour water in a cup with ice cubes before I start making the dough. Mix the dough with your hands at this point to start forming your dough ball.  You don’t want the dough to be too wet. You want just enough water that you can form the dough into a ball. 
5. Once your dough ball is formed, wrap it in plastic and put in freezer for about 15 minutes before rolling it out. 
6. Once out of the freezer, roll the dough out right onto the plastic wrap (that’s important). Have a little extra flour on hand to sprinkle on the dough or your rolling pin if needed so things don’t get sticky. Place the pie plate over the rolled dough to make sure you’ve rolled it out wide enough. It’s enough for a 9” or 10” pie plate.
7. Flip the dough into your pie plate and adjust so it’s even, press down gently in the center to cover the bottom of the pie dish, then carefully peel the plastic away.
8. Fold the edges over the sides and then crimp with a fork around the edge of the entire pie.