Preheat the oven to 400°. In a blender, puree the anchovies, garlic, chile, chicken stock, lemon juice, parsley, rosemary and 3 tablespoons of the olive oil until smooth. In a large roasting pan, preferably nonstick, toss the potatoes, onions and fennel with the anchovy puree. Seasons with salt and pepper and spread them in an even layer. Roast for about 35 minutes, stirring twice, or until just tender.