Mushroom Gratin Casserole {Low Calorie, Low Fat, Healthy, Vegetarian}

This low fat Mushroom Gratin Casserole is made with a homemade white sauce instead of canned soup. Top it with a mixture of cracker crumbs and panko for a delicious, vegetarian side dish.

I adored this casserole! Mushroom Gratin Casserole - Low Calorie, Low Fat, Vegetarian  Holiday Side Dish

When my husband came into my life, Mushroom Gratin Casserole also entered the picture. Another reason to be thankful for my husband. Good friends of his always did a Thanksgiving meal the week before Thanksgiving. One of the specialties was a Mushroom Casserole. This casserole was fabulous; how could it not be with a pint of heavy cream and a stick of butter in it? The mushroom juices mixed with the cream to make the most extraordinary sauce, and was topped with a crunchy mixture of cracker crumbs and butter. One bite and I knew I had to add this recipe to our Thanksgiving menu. Are you thinking Thanksgiving is over? Yes, but this will be fabulous for Christmas, too.

Fourteen years later, I am still making Mushroom Gratin Casserole every year for Thanksgiving. This year though, I decided to take the bull by the horns and lighten it for Christmas. The first step was to get rid of the heavy cream. Boo hoo! The fact that heavy cream was simply poured around the mushrooms made it  easy to make. I still wanted quick and easy without the heavy cream. Thickening some milk and adding some spices was just the ticket. Yes, you have to make a sauce. It only takes about 10 minutes though. That is ten minutes well spent. Then it is simply a matter of pouring the sauce around the mushrooms. I also combined some panko with the cracker crumbs. Panko is lower in fat and sodium but still adds that fabulous crunch. Next the butter, yes, I had to cut down the butter. I still kept a little in this dish to make it feel luxurious. This  is the perfect casserole to serve for Christmas.

I adored this casserole! Mushroom Gratin Casserole - Low Calorie, Low Fat, Vegetarian  Holiday Side Dish

On the face of it, this would not be a typical dish my husband would love. He was born in India and is use to “in-your-face” spices and flavor. Indian food is pungent! This dish is simple and all about simple ingredients. For some reason, it just hits his fancy. It is like his love for Poppy Seed Chicken. Again it is another dish that isn’t full of flavor or spices, but it is just straight comfort food. I am hoping to bring you a homemade (no canned soup) version in January.

Try Low Fat Mushroom Gratin Casserole for yourself. The creamy mushrooms topped with a crunchy, buttery topping will make it a favorite at your house too.  Pin it to your Christmas board so you don’t forget.

I adored this casserole! Mushroom Gratin Casserole - Low Calorie, Low Fat, Vegetarian  Holiday Side Dish

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Yields 9

Mushroom Gratin Casserole {Low Calorie, Low Fat, Healthy, Vegetarian}

5 minPrep Time

45 minCook Time

50 minTotal Time

Save RecipeSave Recipe


  • 11/2 cups 2% reduced fat milk
  • 1/4 cup all-purpose flour
  • 2 garlic clove, peeled
  • 2 sprigs thyme
  • 1 lbs. mushrooms, sliced
  • 1/2 tsp. kosher salt
  • 1/4 tsp. fresh ground black pepper
  • 12 whole wheat Ritz crackers, crushed
  • 1/2 cup Panko bread crumbs
  • 2 tbsp .unsalted butter, melted


  1. Preheat oven to 350°.
  2. In a small saucepan over medium heat, whisk together milk and flour. Add garlic and thyme.
  3. Cook, stirring constantly, until the milk thickens, about 5 to 10 minutes. Turn off heat and let steep for 15 minutes. Remove garlic and thyme.
  4. Spray a 9 x 9 inch baking dish with cooking spray.
  5. Place mushrooms into the baking dish and sprinkle with the salt and pepper. Toss to distribute spices.
  6. Pour thickened milk around the outside of the mushrooms.
  7. Cover with the crushed Ritz and panko. Drizzle with melted butter.
  8. Bake uncovered for 30 to 35 minutes or until bubbly.

Happy Healthy Eating,


But wait, there’s more. Check out these deliciously, low calorie side dish recipes:

Savory Squash Crumble Casserole #sqaushrecipe #thanksgivingside #squashcasserole #healthyside #healthyvegetable #butternutsquashSavory Squash Crumble Casserole

Cheesy and topped with bacon - Healthy & Low Calorie Loaded Mashed Potato Casserole www.fooddonelight.comLoaded Mashed Potato Casserole

Roasted Mushrooms with Tarragon #mushroomrecipe #vegetablerecipe #healthyside #roastedvegetableRoasted Mushrooms with Tarragon


  1. I know this would be a huge hit in my house! Josh and I are both crazy about mushrooms. And who doesn't love a creamy, dreamy sauce?
  2. it looks like you did an excellent job lightening this dish - sounds completely delicious and holiday table worthy for sure
  3. Your ceramic casserole dish is so pretty! Could you please tell me what brand it is so I can find one, too? I'm so tired of plain casserole (or even glass) dishes but I haven't been able to find a pretty embossed one like can bake in it, right? Thank you for reading this.
    • Christie Daruwalla says
      Hi Axia, It is new, was a birthday present. It is Lenox Opal Innocence Carved pattern. You can bake it in. It is also microwave and dishwasher safe. Happy Health Eating, Christie
  4. Kelley Laird says
    Hi Christie, Love the blog-- Langastinos-- what are ideas to do with them?
    • Christie Daruwalla says
      Hi Kelley, Anything that you would do with shrimp will work with langostinos. My favorite is pasta. We had a fantastic pasta with a light wine and garlic sauce with langatinos in Italy. Happy Healthy Eating, Christie


  1. […] you want to be sure to see Food Done Light’s Lightened next recipe, Lightened Mushroom Gratin Casserole, on Thursday be sure to subscribe by email below. You won’t want to miss […]
  2. […] Oven space is at a premium. We can bake a small turkey or stuffing in here. Often times it is my Mushroom Gratin Casserole that is cooked in the De’Longhi oven. The dish fits perfectly in the oven and it cooks […]

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