Sweet Potato Cottage Pie - DANNY'S DELIGHT

Ingredients

• 2 lbs sweet potatoes, peeled and chopped
• 4 oz Greek Yogurt
• 2 tbsp unsalted butter
• 2 tsp cornstarch
• 8 fl oz beef stock
• 1 lb lean ground beef
• 2 medium carrots, thinly sliced
• 1 medium yellow onion, chopped
• 3 cloves garlic, minced
• 2 tbsp tomato paste
• 2 tsp thyme
• 6 oz frozen peas
• 1 tbsp Worcestershire sauce