Killer Scalloped Sweet and White Potatoes in Smoky Hot Sauce

I've totally fallen in love with this easy and healthy version of scalloped potatoes.  These definitely don't taste like the creamy, cheesy scalloped potatoes that often appear on holiday tables, and while I do love that version, these are a nice change of pace (and much healthier to boot).  The cream is replaced with a spicy chipotle-tomato sauce, and half the white potatoes are subbed with sweet potatoes.  I added a bit of goat cheese sprinkled on top just for fun, which adds a great tangy element to the dish.  Even without all the cream and cheese, this is still great comfort food for cold weather.  These potatoes are great as a main dish alongside a big salad or with some crusty bread, or you can serve it in smaller portions as a side along with something like roast chicken.

Killer Scalloped Sweet and White Potatoes in Smoky Hot Sauce (adapted from Mollie Katzen's Vegetable Heaven)
Serves 2 as a main or 4 as a side

1 pound ripe Roma tomatoes
Oil
Generous pinch kosher salt
1/2 tsp minced canned chipotle chiles (more to taste)
1/2 cup skim milk
1/2 tsp salt
1 large clove garlic, minced
1/2 pound Yukon Gold potatoes, thinly sliced
1/2 pound sweet potatoes, peeled and thinly sliced
2 ounces soft goat cheese

1. Preheat the oven to 500 degrees (or as hot as it will get), and move the oven rack to the top slot.  Line a baking sheet with foil.
2. Cut each tomato in half and scoop out the seeds.  Oil the baking sheet and place the tomatoes upside down on the sheet.
3. Roast the tomatoes for 15-20 minutes, until the skins are browned and blistered and the tomatoes are very soft.  Remove from the oven.
4. Turn the oven down to 375 degrees and move the rack back to the middle level. Oil a 1 to 1.25 quart baking dish.
5. Let the tomatoes cool slightly, then slip off the skins.  Combine the tomatoes, a generous pinch of salt, and the chipotle chiles in a blender and blend until smooth.  An immersion blender also works well.
6. Stir the milk, 1/2 tsp salt, and garlic into the hot sauce until combined.  Toss the potatoes together in another bowl.
7. Layer one third of the potatoes into the baking dish.  Cover with a third of the sauce. Repeat with another layer of potatoes and sauce.  Dot the goat cheese all over the potatoes.  Finish with a final layer of potatoes and sauce.  Press down slightly with a rubber spatula and make sure the potatoes are completely covered in sauce.
8. Cover the dish tightly with foil and bake for 30 minutes.  Turn the oven down to 350 degrees and remove the foil from the potatoes.  Bake for another 45 minutes, or until the potatoes are very tender.  Let sit 10 minutes before serving.