Mustardy Caramelized Onion & Butternut Squash Gratin

  By bbqspot      ,

June 24, 2020

  • Yields: 8 Servings


Nonstick cooking spray

¼ cup unsalted butter, 2 tablespoons melted

2 medium yellow onions, halved and thinly sliced

¼ cup yellow mustard

1 tablespoon brown sugar

1 medium butternut squash, peeled, seeded and chopped (about 6 cups)

1 tablespoon plus 1 teaspoon Rub Some Butt™ Carolina Seasoning

½ cup grated Gruyère cheese

½ cup panko breadcrumbs

Sliced green onions for garnish (optional)


8½ x 11-inch baking dish

Large skillet

Chef knife or paring knife

Wooden spoon

Measuring cups

Measuring spoons

Large bowl

Vegetable peeler

Rimmed baking pan

Small bowl

Cheese grater



1Preheat oven to 400°; spray the baking dish with cooking spray.

2In a large skillet, melt the 2 tablespoons of un-melted butter over medium-high heat and heat for 2 minutes.

3Add the onions and cook 10 minutes, stirring occasionally.

4Reduce the heat to low and add the mustard, sugar and ¼ cup water.

5Cook the onion mixture 15 minutes or until the onions are very soft and golden brown, stirring occasionally.

6In a large bowl, toss the squash, 1 tablespoon Carolina Seasoning and 1 tablespoon melted butter.

7Spread the squash in a single layer on a rimmed baking pan and bake 20 minutes.

8Transfer the squash to the prepared baking dish.

9In a small bowl, stir the cheese, breadcrumbs, and remaining 1 tablespoon melted butter and 1 teaspoon Carolina Seasoning. Top the squash mixture with the onion mixture and sprinkle with the breadcrumb mixture.

10Bake the gratin 15 minutes or until the squash is tender and top is golden brown; garnish with onion, if desired. Makes about 6 cups.


Approximate nutritional values per serving (about ¾ cup): 150 Calories, 8g Fat (5g Saturated), 23mg Cholesterol, 385mg Sodium, 19g Carbohydrates, 3g Fiber, 5g Sugars, 4g Protein


To make this dish ahead of time, don’t top the gratin with the breadcrumbs. Cover and refrigerate the gratin and breadcrumb mixture separately for up to 2 days. To prepare the gratin, sprinkle it with the breadcrumb mixture and bake, uncovered, at 400° for 45 minutes or until it’s heated through, squash is tender and top is golden brown.

Try replacing Gruyère cheese with different cheeses such as smoked Gouda, Monterey Jack and/or smoked Cheddar.

2020-06-24T19:37:19-05:00Comments Off on Mustardy Caramelized Onion & Butternut Squash Gratin