Cook the bacon in a large skillet over medium-low heat, stirring often, until the fat has rendered and the meaty bits start to crisp, about 12 minutes. Transfer to paper towels to drain.
Meanwhile, fill a bowl with ice and water. Bring a medium saucepan of water to a boil. Drop in the onions and blanch for 30 seconds. Scoop out the onions with a slotted spoon and plop them in the ice water. Peel the onions by snipping off the tip and removing the papery outer layers. Pat the onions dry.
Nudge the heat under the skillet to medium, toss in the onions, and cook them in the bacon fat, stirring occasionally, until spotted with brown and tender throughout, 8 to 10 minutes. Add the chestnuts, cooked bacon, and honey to the skillet and gently toss until the chestnuts are warmed through, being careful not to cause the fragile chestnuts to crumble. Season the jumble with salt and plenty of pepper and then scoop into a decorative bowl. Sprinkle with the parsley.