In a large bowl, whisk the lemon juice with the mascarpone and lemon zest. Whisk in the olive oil and season with salt and pepper. Add the endives, watercress and onion and toss with the dressing. Place an anchovy fillet on each egg half and arrange the eggs around the salad. Garnish with the pine nuts and serve.
This sharp-flavored salad would be best accompanied by an assertive California Sauvignon Blanc.