Instructions

Cover the cashews with cold water and soak for at least 2 hours or overnight in the refrigerator. Drain and place in a blender and add the oat milk, vegetable stock, miso, nutritional yeast, Dijon mustard, and salt. Blend, scraping down the sides and repeating as necessary until very smooth, then set aside.

Preheat the oven to 400°. Use a slice of vegan butter to grease a 9x13 casserole. Melt 2 Tablespoons vegan butter in a medium sauté pan over medium heat, then add the onions. Sauté, stirring frequently, until soft and clear. Add garlic and thyme leaves, stir for a minute, remove from heat and set aside.

Using a mandolin, or by hand, slice the sweet potatoes into ⅛-inch thick rounds. Move to a bowl. Do the same for the russet potatoes and reserve them on the cutting board.

Arrange a row of sweet potato slices, standing up and shingled, along one long edge of the pan. Arrange a row of russet potato slices alongside it in the same way. Repeat to make four rows, alternating potatoes. Sprinkle with the onion mixture.

Drizzle the cashew sauce evenly over the rows of potato slices, and give the pan a gentle shake to make sure the sauce reaches the bottom. Cover the pan with foil and bake on the bottom rack for 45 minutes. Test the potatoes for doneness by piercing with a paring knife. If they’re not tender, re-cover and bake for an additional 10 minutes.

Uncover, move to the top rack and bake for 15 minutes, then take out and sprinkle with the vegan cheddar shreds if using. Return to the oven for 2 minutes to melt the shreds. Sprinkle with extra thyme if desired.

Let cool for 5 minutes before cutting.