In a large sauce pot, begin to brown the bacon over medium heat, taking care not to burn. When it is sizzling and bubbling, getting crispy, add the onions and begin to caramelize.
Once the onions are soft and have taken on a bit of color, add the garlic and fry that until it becomes fragrant and takes on a subtle brown color.
Add the brown sugar and stir it to a wet caramel, coating everything. Deglaze with the cider vinegar.
Now add your greens and toss with the caramelized ingredients. Let that cook for a minute. Cover with water and throw in a pinch of salt (about 2 tablespoons). Bring to a boil and cook, stirring occasionally, for about an hour or two. If the greens need more time and the liquid is reducing too much, to where the greens are settling on the bottom of the pan, simply add more water and stir.
Once the greens are cooked through, taste your potlikker and add more salt if needed.
In a separate pot or wide saute pan with deep sides, add the heavy cream and slowly reduce by half, careful not to burn or boil over. Once that has become thick, like the consistency of loose mayonnaise, pull out about half of your collards from the potlikker, being sure to strain well (you can add more potlikker if need be but it will be harder to reduce that out). Add to the pan with the reduced cream and toss well, adjust consistency by adding more cream or more potlikker. Taste and adjust seasoning if needed.
Enjoy with some freshly crisped up bacon crumbled on top.