3 tablespoons butter, melted
3 tablespoons extra-virgin olive oil
10 - 12 russet potatoes, peeled
1 small onion or 4 shallots, peeled and sliced very thin
1/2 teaspoon red pepper flakes (optional)
4 - 6 fresh thyme sprigs
About 3 ounces pancetta, cubed
Preheat oven to 375 degrees.
Combine the oil and melted butter in a small dish. Set aside.
Brush a round baking dish (around 9 - 10 inches) with a little of the butter and oil mixture.
Slice the potatoes as thin as possible crosswise. Arrange potatoes vertically in the baking dish. Wedge onion or shallot slices throughout potato slices - in about 3 or 4 sections of each potato. Sprinkle with salt and pepper flakes (use some black pepper if not using red pepper flakes). Brush with the remaining butter and oil mixture.