beef steak (about 300 g) • baby potatoes, diced (about 12 oz or 350 g) • butter (about 30 g) • fresh rosemary, chopped (about 15 g) • cayenne pepper (about 15 g) • fresh parsley, sliced (about 25 g) • onion, diced (about 100 g) • garlic, minced (about 25 g) • Worcestershire sauce (about 25 ml) • lemon juice (about 10 ml) • vegetable oil (about 10 ml) • salt (about 5 g) •