Shepherd's Pie

Name: Shepherd's Pie
Prep time: 10 min
Cook time: 1 h 40 min
Total time: 1 h 50 min
Cuisine: European, British
Ingredients: 1 garlic clove; 20 g olive oil; 180 g onions, quartered; 120 g carrots, cut in pieces; 100 g celery stalks, cut in pieces; 500 g lamb mince, broken in pieces; 30 g tomato purée; 100 g liquid vegetable stock; 1 Tbsp Worcestershire sauce; 1 tsp fine sea salt; ½ tsp ground black pepper; 1 dried bay leaf; 3 sprigs fresh thyme, leaves only; 800 g water; 800 g potatoes, cut in pieces (2 cm); 250 g leeks, halved lengthways then cut in pieces (1 cm); ¼ tsp fine sea salt; 2 pinches ground black pepper; 25 g milk; 25 g unsalted butter, diced