Roasting vegetables: 

Wash and dry vegetables. Cut them in large pieces or chunks. Arrange them on a foil-lined oven pan, drizzled with oil (I use olive), separating them by vegetable. Season with salt and pepper and drizzle with some extra oil.
Bake at medium/low temperature, 300°F/150°C, until slightly charred and crinkled. It may take more or less depending on the vegetable and how large the chunks are. You can cut them in small pieces and it will take much less time. Store them in the refrigerator, in containers (jars are great) with tight-fitting lids and covered in oil. They last a week for sure.
Eggplants - I recommend removing excess water before roasting it. Simply cut it and put in a flat dish with coarse salt. Leave at room t° for about 30 minutes and you will see it released a lot of water (image above). Drain, wipe out the excess salt left (or wash and dry thoroughly) and roast as directed above.

Filling ideas:

Roasted vegetables: they usually include roasted or caramelized onions, bell peppers (I like red peppers but any type can be used), eggplant and zucchini. Sort of a mediterranean quiche. They can be made ahead and kept in the refrigerator for a week.
Ham, bacon and cheese - you can use cold meats in general paired with almost any cheese you have in your fridge. Similar to the Leftover Ham and Cheese Quiche filling. Use the traditional bacon and cheese and you have a crustless quiche lorraine.
Sausage and zucchini - super flavorful, you can use any sausage you like. Cook it without casing and leave out excess fat. Mix with roasted zucchini and cheese.
Caprese - this is the traditional tomato, mozzarella, and basil. Roast the tomatoes as we do in this recipe today. The result is fantastic.
Tomatoes and corn - another great combination, it can be made with frozen corn so it's a breeze to put together.
Mushrooms - cook them in a little oil first (sauteeing). They pair very well with leeks (like the Mushroom Leek Quiche), green onions or chives. And with soft brie cheese.
Broccoli and parmesan or brie - with or without garlic, this is a fantastic combination and you can use frozen broccoli.
Smoked salmon - make it with mostly cream and sour cream and add chopped chives, dill and maybe a smidge of lemon zest.
Only cheese: this is a great idea if you're serving it with meats or a salad. I love to use smoked gouda and/or white cheddar cheese, and some type of soft and melty cheese like mozzarella. 

Storing it

Refrigerator: well wrapped it keeps for at least a week. Warm in a 350°F oven or in the microwave before eating or let come to room temperature.
Freezer: it can be frozen though it's not my first option. Why? Because it adds water that stays in the crustless quiche when defrosted.

Individual ramekins: you can buy these white oval ramekins online, or round porcelain souffle cups which are deeper. Or use a regular muffin tin for even smaller ones.