Preheat the oven to 200°C/gas mark 6. Line a baking sheet with parchment paper.
In a medium bowl, toss together the fennel, pancetta, garlic, brown sugar, olive oil, salt and pepper. Place the ingredients on the baking sheet in a single layer. Cook until the pancetta is crisp and the fennel is caramelised, about 20 minutes. Remove from the oven and let cool for five minutes.
In a large bowl, place the salad greens, crumbled pancetta and caramelised fennel. Toss the salad with the red wine vinaigrette and serve immediately.
Red wine vinaigrette:
Mix the vinegar, lemon juice, honey, salt and pepper in a blender. With the machine running, gradually blend in the oil. Season the vinaigrette, to taste, with more salt and pepper, if desired.