Spinach quiche with caramelized onions is as creamy as custard. Baked in the flakiest herbed crust that will melt in your melt. Great for a Spring brunch or to chase away the winter blues.

Quiche is one of my favorite brunch foods but when ordering it out, I’m rarely impressed with the crust. I normally just eat around it. I’m also kind of picky about what I put in my quiche. I don’t want harsh red peppers but everyone wants to throw them in.
I think that a quiche is the perfect breakfast/brunch food to serve for guests. Yes it has to cook for about 40 minutes but you can do all the prep ahead of time and it doesn’t have to be eaten the minute it comes out of the oven. You can have it all by itself or it’s easy to add fruit or biscuits if you have a really hungry crowd.
The flavors in this version are one of my favorites, sautéed spinach and mushrooms, caramelized onions and a variety of cheeses. The last time I made this we had house guests. So the morning before, I prepped the ingredients. While the onions were caramelizing, I made the pie crust and sautéed the spinach and mushrooms. Once cool, I just put them all in the refrigerator. When I was ready to make the quiche the next morning, I just had to roll out the pie crust and dump everything in.
I used my tried and true recipe for pie crust using butter alone but also added some dried thyme and basil. I rolled it out first thing in the morning and put it in the refrigerator. I went for a run and when I got back, I added the quiche ingredients and put it in the oven. I had plenty of time to get ready while it was baking.
How do you make quiche:
For any quiche if you want it custardy you are going to have to use at least a little cream. Fat free milk will not give you that custard like texture. You don’t have to use all cream though, you can use some whole milk. I like to use at least half heavy cream and then milk for the rest. To get perfect quiche every time, I add six egg yolks to a measuring bowl and fill it up with your milk mixture so that you have a total of three cups. It’s generally about 1 ½ cups of cream. Then you can add anything you like for seasonings and fillings. I almost always add some fresh nutmeg, I just love the flavor it adds to the egg mixture.
Since every oven is different and the ingredients you add may affect the cooking time, you just need to check this after about 30 minutes. You’ll know it’s done when the center doesn’t jiggle when you shake the pie pan.
This is easily adaptable to any ingredients you like, a little bacon or sausage is never a bad choice. You also can do this without a crust at all, just spray the pie pan with cooking spray. Now that you know how to make the perfect custard base, have fun experimenting with your ingredients. It’s a great way to clean out your refrigerator.
Best Ever Spinach Quiche Recipe with Caramelized Onions
Ingredients
- 2 sweet onions thinly sliced
- 1 tablespoon olive oil
- 3 tablespoons butter divided
- ½ teaspoon salt
- pinch sugar
- 2 cloves garlic
- 1 tablespoon olive oil
- 5 cups baby spinach
- 8 ounces mushrooms sliced
- 6 large eggs
- 1 ½ cups heavy cream or whole milk
- 4 ounces gruyere grated
- 4 ounces cheddar cheese grated
- ½ teaspoon salt
- ½ teaspoon black pepper
- ¼ teaspoon nutmeg
- 1 pie crust
Equipment
- Skillets
- Measuring cup
- Measuring spoons
- Mixing bowl
- Pie plate
- Knife
- Cutting board
Instructions
- Preheat oven to 400º. Roll out the pie crust and place it in a deep dish pie pan. Prick with a fork and refrigerate while preparing quiche.
- Add 1 tablespoon olive oil and 1 tablespoon butter to a large skillet. Add onions and toss in oil. Cook on low to medium heat for 15 minutes, then add salt and sugar. Cook for an additional 15 minutes or until golden brown. Set aside.
- In a separate skillet, add 1 tablespoon olive oil and 1 tablespoon butter and heat over medium heat. Add garlic and saute for about 1 minute. Add spinach and a pinch of salt and cook until wilted, about 3 minutes. Remove from pan. In the same pan, add 1 tablespoon butter and saute mushrooms until browned, about 3-5 minutes.
- Add eggs to a large measuring bowl and add enough cream/milk so that the total volume is 3 cups. Whisk until well combined. Add cheese, onions, mushrooms, and spinach. Season with salt, black pepper, and nutmeg.
- Pour into prepared pie crust. Turn oven down to 375º and bake for 40-50 minutes until the center no longer jiggles.
Barbara’s Tips + Notes
- Quiche can be made ahead as desired. You can eat this quiche hot, warm, or at room temperature.
- Feel free to use leftover veggies in your quiche if you have some in the fridge.
- If you’re not sure if your quiche is cooked adequately, use a toothpick or knife to test it. Insert it into the middle of the quiche, and if it comes out clean, it’s done baking.
- Don’t bake your quiche at a high heat. Rushing your quiche makes your quiche rubbery. Allow it to bake at 375 for the full time.
Perfect description of the best way to make quiche! Anything with caramelized onions works for me. Your writing just inspires me!
The best quiche I have ever made or been served…crust recipe meets all of my expectations of a perfect crust. Can’t wait to try it in a double crust recipe!! Love your blog!
I’m so glad you liked it, I find myself making it all the time. You might also like the same quiche in a sweet potato crust. https://www.butterandbaggage.com/quiche-sweet-potato-crust/. Thanks for following the blog. Check out Facebook or Instagram for daily updates.