Place a medium-sized skillet over medium-high heat with 1 turn of the pan of EVOO, about 1 tablespoon. Once hot, add the bacon and cook stirring every now and then until crispy, about 5 minutes. With a slotted spoon, remove the bacon from the skillet to a paper towel-lined plate.
Remove all but about 2 tablespoons of the fat from the skillet, return the skillet to the heat and add the onion to the pan and cook until tender, about 3-4 minutes. Remove from heat and combine with the bacon. Season with some pepper and let cool.
Lay the pastry dough out on a nonstick baking sheet. Spread the Boursin evenly over the dough then top with the bacon-onion mixture. Sprinkle with Swiss cheese.