Vegetarian Shepherd's Pie

Ingredients

• 6 Yukon Gold potatoes, peeled
• 1/4 cup butter or olive oil
• 1/2 cup full-fat Greek yogurt
• salt, to taste
• 2 tablespoons olive oil
• 3 shallots, minced
• 1 (16-ounce) carton fresh mushrooms, sliced
• 6 carrots, peeled and chopped
• 1 rosemary sprig
• thyme, to taste
• 1 bay leaf
• 2 tablespoons tomato paste
• 2 tablespoons flour
• 1/2 cup red wine
• 2 cups vegetable broth
• 1 teaspoon salt
• 2 cups frozen peas