Vegetable Shepherds Pie

Soak the dried porcini mushrooms in 3 cups of hot water; set them aside to rehydrate.

In a medium saucepan, combine the lentils, 1 garlic clove, 1 tsp. salt, and 4 cups of water. Bring the mixture to a boil, then reduce the heat and simmer, stirring occasionally, until the lentils are tender but still hold their shape, about 15–20 minutes. Drain the cooked lentils and discard the garlic clove.

Heat 3 Tbsp. of olive oil in a large, heavy pot over medium heat. Add the chopped onions and cook, stirring occasionally, until they're soft and translucent, about 12 minutes. Stir in the chopped garlic and cook for just 1 minute, until fragrant.

Add the tomato paste and cook, stirring constantly, for 2–3 minutes, until it darkens in color and caramelizes slightly.

Strain the sauce mixture into a large saucepan, discarding the solids left in the strainer. Bring the strained sauce to a boil.

In a small bowl, whisk together the cornstarch and 2 Tbsp. of water until the cornstarch is fully dissolved. Stir this mixture into the simmering sauce and continue to simmer until it has thickened enough to coat the back of a spoon, about 5 minutes. Whisk in the miso, then season the sauce with salt and pepper to taste. Set the finished sauce aside.

Preheat your oven to 450°. In a large bowl, toss the chopped mixed vegetables and pearl onions with the remaining 2 Tbsp. of olive oil, 5 garlic cloves, and rosemary sprigs. Season with salt and pepper, then divide the vegetables evenly between 2 rimmed baking sheets.

Roast the vegetables, stirring once halfway through, until they are tender and lightly browned, about 20–25 minutes. Transfer the roasted garlic cloves to a small bowl, mash them well with a fork, and stir them into the prepared sauce. Discard the rosemary sprigs. If you're working ahead, the lentils, sauce, and roasted vegetables can all be made up to 1 day ahead; cover them separately and chill.