- 2 tablespoons olive oil
- 2 leeks, white and light green parts thinly sliced
- 2 cloves garlic, minced
- 2 delicata squash, ends removed and hollowed out
- 1 large unpeeled russet potatoes, scrubbed clean
- 1 large unpeeled sweet potato, scrubbed clean
- 3 small Granny Smith apples
- 4 eggs
- 1 cup heavy cream
- 1/4 cup grated Parmesan cheese
- Leaves from 6 sprigs fresh thyme
- zest from 1 orange
- 1/4 teaspoon crushed red pepper flakes
- Kosher salt to taste
- Freshly cracked black pepper
- Maldon salt
- thyme leaves
- Heat oil in a 9-inch cast iron skillet over medium heat. Add the sliced leeks and a generous sprinkle of kosher salt to the skillet. Cook for 5-8 minutes, stirring frequently, until the leeks are translucent. Add the garlic and cook for 1 minute more until fragrant. Remove from the heat, spread evenly in the bottom of the pan, and allow to cool.
- While the onion mixture is cooling use a mandoline to slice the delicata squash, russet potato, sweet potato, and apple into very thin slices that are about the same thickness as a potato chip. **Have a bowl of cold water ready to submerge the apple slices into so that they do not turn brown.**
- Starting at the outer edge of the skillet, with the cooled leeks on the bottom, make a pinwheel pattern with the squash, potato, and sweet potato slices working towards the center. Add an apple slice every fourth time the squash and potato pattern repeats. Repeat this process until the skillet is packed tight and filled to the center.
- Preheat the oven to 375°F. In a mixing bowl whisk together the eggs, heavy cream, Parmesan, thyme leaves, orange zest, red pepper flakes, salt, and pepper to taste until completely combined. Pour the egg mixture over the vegetables in the skillet allowing the mixture to settle into the vegetables.
- Bake in the preheated oven, covered with foil, for 40 minutes. Remove the foil and bake an additional 40-45 minutes until the vegetables are crisp on the outer edges and tender in the center, the custard is set, and the top is nicely browned. **To check if the vegetables are done carefully remove a thin slice of potato or sweet potato from the center of the pinwheel and taste to make sure it is cooked through.**
- Remove the tian from the oven when the vegetables are cooked through and allow to cool slightly. Sprinkle with more thyme leaves and Maldon salt flakes right before slicing to serve.
If the tops of your veggies aren’t quite a s crispy as you want at the end of the bake time turn the broiler on for a few minutes- just watch the tian closely so it doesn’t burn.