Quarter potatoes, skin on, and boil them in 8 cups of water with a teaspoon of salt for approximately 20 minutes, or until tender to the poke of a fork. Drain water.
In your best large nonstick pan or well-seasoned skillet, over medium-high heat, add 1 tablespoon butter and 1 tablespoon olive oil. When the butter/oil mixture is hot, transfer potatoes to pan and use a spatula to chop the quarters into smaller pieces (there is no science here). As the potatoes absorb the butter and oil during cooking, continue to add equal amounts of each, as required, to keep the pan well greased. Saute for 20 minutes, turning occasionally, or until potatoes begin browning on all sides. If the potatoes start burning before they brown, reduce the heat.
Add garlic, and onions and continue cooking for 15 more minutes, or until potatoes, garlic and onions are all very browned and crispy.
When it seems potatoes are almost done to your liking, add herbs, salt, and pepper to taste and toss well. Serve immediately on warmed plates.
It's all in the timing of adding the garlic and onions (which can only really be learned through trial and error). Adding them too soon will cause them to burn before the potatoes are crisp, and too late will prevent the garlic and onion from fully caramelizing.