As with any quiche you can add whatever ingredients you want. I had some broccoli in the fridge so I added that with tons of cheddar and boy was this quiche delicious.
Make and roll out your crust and place it in a greased pie tin.
Poke holes in the base of the crust; line it with aluminum foil and pastry weights (dried beans or rice work just fine) and bake in your pre-heated oven for about 15 minutes. (be sure to cover all the crust with aluminum foil so none of it burns)
While the crust is baking, prepare the shallots and broccoli.
Steam the broccoli in a colander above boiling water until it just softens, and turns bright green.
Melt the butter in a sauté pan, and cook the shallots over medium high heat, until they begin to caramelize, about 5 minutes.
Beat the eggs together with the sour cream, generously salt and pepper and set aside.
Remove the crust from the oven, and take off the aluminum foil and weight.
Using a spoon, spread the Dijon mustard across the base of the crust.
Evenly spread the cooked shallots over the mustard; add the broccoli and cheese, then pour the egg mixture over the top.
Return the pie to the oven and cook until beginning to brown and set, about 20 – 25 minutes.