The walnuts in the sauce and topping of this creamy gratin make for a satisfying dose of good fats and protein. This cozy dish is perfect with a little side salad. My gratin method here works with all kinds of thinly sliced vegetables, including potatoes and sweet potatoes, and even small florets of broccoli and cauliflower. Nutritional yeast (an inactive yeast) is what brings the slightly cheesy and savory flavor. It can be found in spice aisles of supermarkets.
Per serving:
Preheat oven to 375 F. Lightly grease 7 x 11 x 2 inch baking dish with olive oil. If you donu2019t have this size, any baking dish with a 6 cup capacity will work.
Make topping: In food processor or the dry blade container of a high-speed blender, combine all topping ingredients. Pulse mixture until you have a crumbly, slightly moist consistency. Set aside.
Make walnut sauce: In medium saucepan, combine diced potato, walnut halves and garlic. Cover with cold water and set pot over medium-high heat. Bring saucepan to a boil and then simmer until potatoes are tender and falling apart, about 15 minutes. Drain and allow to cool slightly.
In upright blender, combine drained potato and walnut mixture, nutritional yeast, lemon juice, olive oil, mustard, water, salt and pepper. Blend mixture on high until completely smooth and creamy.
Spread 1/2 cup walnut sauce across bottom of prepared baking dish. Arrange slices of zucchini in dish. Lightly season arranged zucchini with salt and pepper. Pour remaining walnut sauce overtop zucchini. Lightly tap baking dish on the counter a few times to evenly distribute sauce.
Cover baking dish with foil and bake in oven for 15 minutes. At the 15 minute mark, remove foil from baking dish, and sprinkle topping evenly across the surface. Bake gratin for another 15 minutes, or until sauce is bubbling and slightly thickened and topping is lightly browned. Serve gratin hot.