Sauté the bacon in a large pan over medium heat until golden brown, about 10 minutes. Remove the bacon from the pan with a slotted spoon, leaving as much grease as possible in the pan, and set aside to drain on paper towels.
In the pan with the bacon fat, sauté the onions until translucent, for about 5 minutes.
Remove the onions from the pan, leaving behind any remaining bacon fat.
Add the vegetable oil to the bacon fat and heat over medium-high heat.
Add the potatoes to the pan. Season with salt and pepper and sauté the potatoes until they begin to get a golden crust, 15-20 minutes.
Return the bacon and cooked onions to the pan and toss gently with the potatoes. Sauté for another 5 minutes, until everything is heated through and golden brown.
Transfer to a serving bowl and garnish with parsley.