Cut and trim the tough stems away from the collard leaves. Stack the leaves, roll tightly and slice into ribbons. Wash the ribbons thoroughly and set aside to drain. Dice the onion and the garlic.
Cut the bacon into 1-inch pieces. Heat the olive oil in a large deep pot over medium heat and add the red pepper flakes and bacon. Cook until the fat renders out and the bacon is getting crispy. Remove the bacon with a slotted spoon.
Add the onion and garlic and turn the heat to low. Cook them slowly in the bacon fat, stirring frequently, until soft and golden. This should take at least 10 minutes. Turn the heat lower if they begin to darken.
Add the collard greens and bacon, stirring until wilted. Pour in the wine and chicken broth and season with a little salt and pepper. Bring to a low simmer, cover, and cook for as long as it takes to reach the tenderness you prefer. I like soft, tender greens with just a slight bite, which took about 30 minutes over low.
When finished you can remove the lid to let the pot liquor evaporate more, or not - it's delicious poured over rice. Season if necessary with more salt, pepper, and a smoky touch of chipotle.