Cauliflower & Potatoes With Black Mustard Seeds

• 15 fenugreek seeds
• 2 serrano chiles (fresh)
• 1 cauliflower
• 1 tomato
• 375 gr cubed potatoes (new)
• 90 ml peanut oil
• 18 gr garlic (minced)
• 18 gr cilantro leaves (chopped)
• 16 ml lemon juice
• 10 ml black mustard seeds