Warm the butter and oil in a soup pot and add the onion, white carrots, rice, 1 teaspoon salt, and the sugar and thyme. Cook over medium heat for several minutes, turning everything occasionally. Add 1 cup of the water, cover, turn down the heat, and cook while you heat the remaining 3 cups water. When the water is hot, add it to the pot, cover, and simmer until the vegetables are tender, about 20 minutes.
While the soup is cooking, cook the diced carrots in salted boiling water for about 3 minutes and then drain.
When ready, let cool slightly, then remove and discard the thyme sprig. Puree the soup until smooth in a blender. Taste for salt and season with the pepper. Reheat if it has cooled.
Ladle the soup into bowls, scatter the diced carrots and carrot tops over each serving, and serve.
Heat the oven to 375°F. Lightly oil a small baking dish; a round Spanish earthenware dish about 6 inches across is perfect for this amount.
If your ricotta is wet and milky, drain it first by putting it in a colander and pressing out the excess liquid. Pack the ricotta into the dish, drizzle a little olive oil over the surface, and bake 20 minutes or until the cheese has begun to set and brown on top. Cover the surface with the bread crumbs and continue to bake until the bread crumbs are browned and crisp, another 10 minutes. (The amount of time it takes for ricotta cheese to bake until set can vary tremendously, so it may well take longer than the times given here, especially if it wasn’t drained.)
When the cheese is finished baking, heat the butter in a small skillet over medium heat. When the butter foams, add the shallots and sage and cook until softened, about 3 minutes. Add the peas, 1/2 cup water, and the lemon zest. Simmer until the peas are bright green and tender; the time will vary, but it should be 3 to 5 minutes. Whatever you do, don’t let them turn gray. Season with salt and a little freshly ground pepper, not too much.
Divide the ricotta between 2 plates. Spoon the peas over the cheese. Grate some Parmesan over all and enjoy while warm.
With Pasta: Cook 1 cup or so pasta shells in boiling, salted water. Drain and toss them with the peas, cooked as above, and then with the ricotta. The peas nestle in the pasta, like little green pearls.