The Best Vegetable Au Gratin

This post is sponsored by Copper Chef. Like always I’m keeping it real and all opinions are my own. Thanks for supporting brands that support Whole Living Lauren!

There is a heat advisory this week and here I am posting an au gratin recipe! 2 weeks ago we were spoiled with gorgeous weather that got me excited for fall. The mornings were cool, the air had a crispness to it, it was sunny, and just incredibly pleasant. Fast forward to this week and it feels like a sauna outside. I made the mistake of going on a run outside at 9am earlier this week and it was one of the worst decisions I have made in a while. And I’m not even exaggerating one bit. 

Despite the fact that it currently feels like the surface of the sun outside, I’ve been thinking about fall foods. The beautiful weather got me excited! But can we talk about something else? I saw Halloween decorations up and for sale at the grocery store this week. I repeat…. HALLOWEEN DECORATIONS. What in the world?! As excited as I am about fall, Halloween decorations up in late August/early September is a little aggressive. Please tell me I’m not the only one who thinks this is absolutely absurd! 


But let’s talk food! The recipe I am sharing with you today is a dish that embodies the perfect combination of both summer and fall. A flavorful au gratin that uses a mix of potatoes and summer veggies. It’s also vegan, gluten-free, creamy, and delicious!


But the coolest part about this dish is that I cooked it in the Copper Chef Wonder Cooker. Have you heard of it?! Scott and I have actually been admiring this line of cookware for a while. We have seen it advertised on TV and have been curious to try it. The Wonder Cooker appears to be an ordinary cooking pot, but upon closer inspection, you’ll find that it has a design that allows it to be used in several different ways. It acts as a double cooker, shallow roaster, grill pan, roaster, and Dutch oven. It actually has 14 different cooking functions! Induction plates are on the pans and lids which makes it a super effective heat conductor. 


For this recipe, I used the shallow pan on the stove top to sauté the onions and garlic then put it in the oven to finish baking. Yep….I used the same pan for both sautéing and baking! You know I like when things are efficient and this made me super excited (it’s the little things, right?!). This pan conducts heat so well and evenly. I was able to easily sauté the onions and garlic, then layer the rest of the veggies, sauce, and toppings on before sticking it in the oven to bake. Voila! 


I loved using a mixture of potatoes and veggies for this recipe. It kept things light and fresh, yet still hearty and comforting. You could switch up the veggies if you want, but I highly suggest this combo. It definitely hit the spot!


Curious to try the Copper Chef Wonder Cooker yourself? The Copper Chef team and I have teamed up to give away a Wonder Cooker to one of you as a thank-you for reading and supporting Whole Living Lauren! Click the link HERE for more details and enter to a win one of your own! ALSO, save 20% OFF when you shop using the code: WC20A (only valid on!

Happy cooking, friends!

Vegetable Au Gratin

| Yields 6-8 servings |


  • 1.5 Tbsp extra virgin olive oil
  •  1 small yellow onion, sliced
  • 2 cloves garlic, minced
  • 3 medium potatoes (I used a mix of sweet potatoes and Russet)
  • 3 medium zucchinis
  • 4 carrots, peeled
  • 1 bunch asparagus
  • 2 cups plain, unsweetened almond milk
  • 1 tsp dried parsley
  • 1 tsp dried thyme
  • 2 Tbsp corn starch
  • ¼ cup nutritional yeast
  • Sea salt and black pepper to taste

For the topping:

  • 1 cup raw cashews
  • ½ cup nutritional yeast
  • 2 tsp lemon zest
  • ½ tsp garlic powder
  • 1 tsp sea salt
  • ½ tsp black pepper


  1. Preheat the oven to 350 degrees F.
  2. Thinly slice the potatoes, zucchini, and carrots, into about 1/8th thick slices. Use a mandolin if you have one, or just use a sharp knife and eyeball it.
  3. Cut the top 2-3 inches off the asparagus. This is the only part you will be using for this recipe. Save the rest for another recipe if possible!
  4. Place the olive oil and garlic in the Wonder Cooker’s Shallow Pan, place on the stove top, and cook the onions over low heat for about 5-7 minutes.
  5. In a small saucepan, whisk together the almond milk, parsley, thyme, and corn starch. Bring to a simmer and stir constantly until the mixture starts to thicken. It should be about the consistency of alfredo sauce. Whisk in the nutritional yeast and turn off the heat.
  6. Arrange half the sliced vegetables over the sautéed onions. Pour ¼ - ½ of the sauce evenly over the vegetables.
  7. Arrange the remaining vegetables, then top with the remaining sauce.
  8. Make the gratin topping by putting the cashews in the food processor and pulsing until they are the consistency of bread crumbs. Add the nutritional yeast, lemon zest, garlic powder, salt and pepper and pulse a few more times until mixed. Sprinkle evenly over the vegetables.
  9. Cover the Wonder Dish with aluminum foil and bake for 45-50 minutes. Garnish with fresh or dried rosemary if desired.
  10. Enjoy!