• Let the ricotta come to room temperature.
• Peel and finely chop the shallot.
• Finely chop enough garlic to measure 1 teaspoon.
• Strip the thyme leaves from the stems.
• Strip the parsley leaves from the stems; coarsely chop the leaves.
• Zest and juice the Meyer lemon, keeping the zest and juice separate.
• Coarsely chop the walnuts.

In a medium pot over medium heat, warm 1 to 2 tablespoons oil until hot but not smoking. Add the squash, shallots, and garlic, season with salt and pepper, and cook, stirring occasionally, until the squash begins to soften and caramelize, 8 to 10 minutes.
Add the rice and thyme and cook, stirring occasionally, until fragrant, about 1 minute.

Add ½ cup wine or water to the rice and cook until the liquid reduces slightly, 2 to 3 minutes. Pour in 2½ cups of water. Bring to a boil, reduce to a simmer, and cook, stirring occasionally, until most of the liquid has been absorbed and the rice is just tender, 15 to 18 minutes. Remove from the heat and stir in the Parmesan and half the lemon juice. Season to taste with salt and pepper.
While the risotto cooks, prepare the ricotta.

In a bowl, combine the ricotta cheese, parsley, lemon zest, and remaining lemon juice. Mash with a fork until blended.

Transfer the risotto to individual bowls. Garnish with the ricotta and walnuts and serve.