Sorry, but caramelizing onions is going to take at least an hour of your time.
Here's the thing about caramelizing onions: It takes a while. Not 15 minutes. Not 30 minutes. For me, on my stove, it almost always takes at least an hour, and usually closer to 90 minutes. I'm sorry about this. I wish I could fix it. Caramelized onions are delicious, and if I could have them more rapidly, I would make them more often. But if any recipe tells you that you can get that deep brown color and complex sweet-umami flavor from caramelized onions in ten minutes, it is a lie and you should disregard it.
The number one thing that goes wrong with caramelized onions is impatience.
You can't cook them at a high temperature. This means that the onions will burn before they really caramelize, and you'll have wasted all that work and a couple of onions, too. The way to caramelize onions is low and slow, at a pace that is somewhere between infuriating and meditative. It's possible that you aren't adding enough fat to the pan at first, and that your onions are sticking. That could be a problem, too. If you're way overly cautious and the flame is very, very low, it could also take a lot longer than 90 minutes, though the flavor will probably also be terrific.
We want onions to caramelize faster because none of us have time to wait around for that. We want 30-minute dinners, something fast and easy on a Tuesday. There is absolutely nothing wrong with that. There's no wrong way to feed yourself. There is, however, a wrong way to caramelize onions, unfortunately. So save it for when you know you have time, and then use those precious, delicious onions to add flavor to all kinds of things. You can make a killer French onion dip. You can add it to macaroni and cheese. You can make this gorgeous mushroom and chicken penne. You can make French onion pot pie, or good old-fashioned French onion soup. The world is full of possiblities for your hard-won caramelized onions. All you need to do is take your time.