Shepherd’s Pie with Sweet Potatoes

Ingredients

• 2 medium sweet potatoes, peeled and diced into 1-inch (2.5 cm) cubes
• 1 tbsp / 15 ml margarine or butter
• 1 tbsp / 15 ml olive oil
• 2 cups / 500 ml finely diced onion
• 2 cups / 500 ml sliced mushrooms
• 2 lb / 900 g lean ground beef
• 6 garlic cloves, crushed
• 1 cup / 250 ml sodium-reduced beef stock
• 1 tbsp / 15 ml flour
• 1 tsp / 5 ml Worcestershire sauce
• 1/2 tsp / 2 ml coarse sea salt, or to taste
• freshly gound black pepper, to taste
• pinch red pepper flakes, or to taste
• 1 1/2 cups / 375 ml corn kernels, fresh, frozen or canned (no added salt)