Boil 4 quarts of water in a large pot. Chop 12 slices of bacon into bits; place the bits in a stainless steel skillet; slowly brown while rendering fat. When bacon is brown, remove bacon from skillet (saving the bacon fat); set aside.
Roll up bunches of collard greens cigar-style and slice into 1/4-inch slices.
Place sliced greens in boiling water. Return skillet with bacon fat to heat; add thinly sliced onions; sauté for 1 minute.
Using tongs, remove greens from water and place in skillet.
Add black pepper and apple cider vinegar; cook for 5 minutes.
Garnish with bacon bits.
Honey mustard drizzle: Whisk together all ingredients in a bowl. Drizzle over greens.