Bring a large pot of salted water to a boil and add tagliatelle. Cook according to package directions or until just al dente. Drain, reserving 1/4 cup (50 ml) pasta cooking water.
Heat 1 tbsp (15 ml) olive oil in a small skillet over medium heat. Add 1 tsp (5 ml) chopped garlic and breadcrumbs and sauté until breadcrumbs are crisp, about 2 minutes. Stir in 1 tbsp (15 ml) chopped parsley, season with salt and transfer to a bowl. Reserve.
Heat remaining 3 tbsp (45 ml) oil in a large skillet over medium-high heat. Add leeks and sauté for 1 minute or until slightly softened. Add mushrooms and remaining 2 tsp (10 ml) garlic and cook for another 3 minutes or until mushrooms are limp and exuding some juice. Stir in lemon rind and 2 tbsp (30 ml) lemon juice. Add stock and basil leaves and cook for 30 seconds or until basil has just wilted. Season well with salt and pepper.
Toss tagliatelle with mushroom and lemon mixture. Stir in reserved pasta cooking water, remaining 1 tbsp (15 ml) lemon juice, remaining 1 tbsp (15 ml) parsley and extra-virgin olive oil. Toss with breadcrumbs. Divide pasta between 4 individual serving plates and serve immediately.
Per serving: 610 calories, 20 g total fat, 3 g saturated fat, 13 g monounsaturated fat, 3 g polyunsaturated fat, 90 g carbohydrates, 22 g protein, 0 mg cholesterol, 7 g fibre, 90 mg calcium, 92 mg magnesium, 190 mg sodium, 1083 mg potassium, 3 mg vitamin E, 6.3 mg iron, 35 RE vitamin A, 21 mg vitamin C