Preheat the oven to 425°F.

Add the mushrooms and shallots to a large rimmed sheet pan. Drizzle with 2 tablespoons olive oil and the soy sauce, season with salt and pepper, and add the thyme sprigs. Toss well and spread into a single layer.

Roast for 20–25 minutes, until the mushrooms have released their liquid and are beginning to brown deeply. Meanwhile, toss ¾ cup of the cooked lentils with the remaining 1 tablespoon olive oil.

Remove the pan from the oven and add the oiled lentils. Toss everything together, then return the pan to the oven for another 10–15 minutes, stirring once, until the mushrooms are deeply browned, the shallots are soft and golden, and some of the lentils have crisped around the edges.

While everything finishes roasting, melt the butter in a small saucepan over medium-low heat. Add the garlic and cook gently for about 30 seconds, just until fragrant. Whisk in the miso and honey until smooth. Add 1 tablespoon water, then a little more if needed to make a silky, pourable sauce.

Add the remaining ¾ cup tender lentils to a large serving bowl. Remove the thyme stems from the roasted mushroom mixture, then add the mushrooms, shallots and roasted lentils.

Pour the warm garlic miso butter over everything and toss gently to coat. Add the green onions, lemon zest, lemon juice and plenty of freshly ground black pepper. Taste and adjust the seasoning as needed.

Serve warm, with crusty bread or on a bed of arugula.