Pre-heat the oven to 350° F.

Stir the cornmeal, flour and salt together in a bowl. In another bowl, whisk the oil and water until it is thick and creamy. Pour over the flour, all at once. Mix with your fingers until blended and the wet part picks up any dry parts in the bowl.

Lightly oil a 9-inch tart pan with a removable bottom. Press the dough into the pan, pressing up the sides and evenly into the corner and top of the fluted edge.

Line the dough with a sheet of parchment paper and fill it with dried beans or rice. Bake the crust for 30 minutes. Remove from the oven and allow to cool. Remove the paper with the beans.

Slice the leeks very thinly. Heat the olive oil over medium flame in a skillet. Add the leeks and cook and stir, helping to break up the leek rings with a wooden spoon. When they are soft, reduce the flame to low, add the water and cover. Cook for 10 minutes or so, adding water if needed to keep the leeks fairly moist.

In a blender place the tofu, lemon juice, salt and olive oil. Puree until very smooth, stopping to scrape down the sides or to help everything break up so the blender does its job.

Raise the oven heat to 375° F. Remove the lid from the leeks. Cook until the liquid evaporates and the leeks are very soft.

Scrape into the pre-baked crust. Sprinkle with 3 ounces of the cheese, about a third.

Pour the tofu filling over the cheese and spread to the edges. Distribute the remaining cheese over and to the edges of the tart. Sprinkle with the thyme, if using.

Cool at least 10 minutes before cutting. Serve hot, at room temperature, or cold.