This was sort of like a cheeseless gratin. It would have been even better with gruyere melted on top, but I wanted to make a vegan dish. It was still delicious, and very light. After caramelizing the fennel and leeks in olive oil I layered them with the potato slices and fresh thyme, and then filled the dish with just enough vegetable stock to reach the top layer. As the potatoes cooked they absorbed all of the stock and held together nicely when sliced into portions.
This is a very light, yet robust sauce without any butter - only a small amount of olive oil, shallots, dijon, parsley, capers and lemon juice in a reduction of pinot grigio. I did not saute the scallops, but merely poached them briefly in the sauce.
A velvety combination of egg yolks, lemon zest, Pecorino Romano and black pepper. I first tempered the yolks with the salty, starchy pasta water before whisking in the lemon zest and parsley and tossing all the ingredients together right before serving.