Trim the ends off the endives and radicchio, being careful to remove as little as possible so the leaves stay attached to the core and the veggies remain intact. An eighth of an inch should do the trick; You only want to remove the brown, dried out part. Cut the endives in half lengthwise and the radicchio in 4 quarters.
Set a large, heavy skillet over medium heat and cook the bacon until it gets nice and crispy, then remove it to a plate with a slotted spoon, leaving the fat in the skillet.
Place the endives and radicchio cut side down into the pan and cook for 3-4 minutes, until the vegetables start to crisp up and turn nice and golden brown.
Carefully flip the endives and radicchio with kitchen tongs, dribble with 2 tablespoons of the maple syrup and sprinkle generously with salt and pepper. Continue cooking for an additional 2 to 3 minutes, until the vegetables are soft and tender. Remove to a serving platter.
Deglaze the pan with the last tablespoon of maple syrup and white wine vinegar then add the chopped pecans and continue cooking until the syrup thickens, which will only take a few seconds to a minute.
Pour that over the reserved vegetables, sprinkle with the reserved crispy bacon and serve immediately with your favorite protein.