Pithivier with Mushrooms, Leeks, and Potatoes

Name: Pithivier with Mushrooms, Leeks, and Potatoes
Prep time: 1 h 30 min
Cook time: 40 min
Total time: 2 h 10 min
Cuisine: French
Ingredients: 2 medium potatoes, cubed (about 500 grams, or 4 cups cubed potatoes); 2 leeks, sliced (white and pale green parts only; about 300 grams or 4 cups sliced leeks); 225 grams mushrooms, sliced (about 3 1/2 cups); 3 cloves garlic, peeled and finely chopped; 1-2 tablespoons olive oil, for sautéeing; 1 cube vegetable bouillon; 1 tablespoon water; 1 teaspoon dried thyme; 1/2 teaspoon dried rosemary; 1/4 teaspoon ground nutmeg; Pinch red pepper flakes (optional); Salt and pepper, to taste; 2 sheets puff pastry, thawed according to package directions if frozen; 85 grams gruyere cheese, grated (about 3 ounces, or 1 cup grated cheese); 85 grams parmesan cheese, grated (about 3 ounces, or 1 cup grated cheese); 2 egg yolks, lightly beaten; Red gel food coloring (optional)