How to Make It
Put the potatoes in a medium saucepan, cover with water and bring them to a boil. Add a large pinch of salt and boil over moderately high heat until the potatoes are tender, about 35 minutes. Oil an 8-inch square glass baking dish.
Meanwhile, in a medium skillet, melt the butter. Add the shallot and garlic and cook over moderate heat until softened, about 3 minutes. Add the bacon and cook until most of the fat has been rendered, about 3 minutes. Add the oats and cook, stirring, until lightly golden, about 2 minutes. Remove from the heat and stir in the parsley and thyme.
Drain the potatoes and peel them. Halve each potato crosswise. Working over a bowl, pass the hot potatoes through a ricer. Alternatively, mash the potatoes by hand until smooth. Stir in the oat mixture and season with salt and pepper. Spread the potatoes in the prepared baking dish. Cover with plastic wrap and refrigerate until firm, at least 1 hour.
Bring the potato mixture to room temperature. Cut the potato mixture into 4 squares, then cut each square in half again. Carefully lift the cakes out of the dish with an offset metal spatula. In a large nonstick skillet, heat 1/4 cup of the vegetable oil until shimmering. Spread the flour in a shallow bowl and season with 1/2 teaspoon of salt. Carefully dredge each potato cake in the flour; shake off any excess. Add the potato cakes to the skillet and cook over moderately high heat until browned, about 2 minutes. Turn the cakes and add the remaining 2 tablespoons of oil to the skillet. Cook the cakes until richly browned and heated through, about 2 minutes longer. Transfer the potato cakes to a platter and serve hot.