Root Vegetable Gratin

Ingredients:

• 450 g sweet potato, peeled and cut into 0.5 cm thick slices.
• 450 g celery root, peeled and cut into 0.5 cm thick slices.
• 450 g potatoes, peeled and cut into 0.5 cm thick slices.
• 1.5 cups chopped onion (1 large onion)
• 2 cups fennel (cut into 1/4-inch thick slices, top and core removed)
• 1 tbsp. minced garlic (3 cloves)
• 2.5 cups heavy cream
• 0.5 cup chicken broth
• 2 tbsp. grated Gruyère cheese (180 g with rind)
• 2 tsp chopped fresh thyme leaves
• 2.5 cups large fresh bread crumbs, crust removed

Preparation:

1. Preheat oven to 175°C. Grease a 32 x 25 x 6 cm baking dish with butter.
2. In a large (30 cm) skillet, heat 2 tablespoons of olive oil over medium heat. Add the onion and fennel and cook for 10 minutes, stirring occasionally, until the vegetables are lightly browned and softened. Add the garlic and cook for 1 minute.
3. Meanwhile, in a large bowl, combine the onion mixture, sweet potato, celery root, potatoes, cream, chicken broth, Gruyere, thyme, 1 tablespoon salt, and 1.5 teaspoons pepper. Pour the mixture into the prepared baking dish and press lightly to seal the vegetables to the edge. Combine the breadcrumbs and 2 tablespoons olive oil and spread evenly over the vegetables.
4. Prepare the gratin while the turkey is resting. Bake, uncovered, for 1 hour and 30 minutes, until the vegetables are very tender when pierced with a small knife and the top is golden brown and bubbly. Let rest for 15 minutes, then serve the gratin hot.
   
   Tips for Preparing for Future Use
   
   Assemble the gratin, cover and refrigerate for up to 24 hours, then bake it before serving..