Heat oven to 350°F. Butter an 8-inch baking dish, round or square.
In a medium pot, cover squash with cold water, place a lid on top and bring to a boil over high heat. When boiling, reduce heat so that the water just simmers and cook squash for about 15 min. or until tender. Rinse under cold water; drain. (Do-Ahead: at this point the squash can be stored for up to two days until you are ready to assemble the gratin.)
Heat olive oil in a non-stick pan and add onions. Sauté on medium heat, stirring often, until softened. Set aside to cool slightly.
In a medium bowl, beat egg, salt and mayonnaise together. Add 1/3 cup of Parmesan, panko, sautéed onion and squash and fold together gently to combine. Season with pepper and more salt, if needed.
Spoon in to prepared baking dish and top with remaining 1/3 cup of cheese. Bake 1 hour or until heated through and cheese is slightly browned. Serve hot.
Nutitrion
Serving Size: 1 serving
Calories: 120 kcal
Carbohydrates: 10 g
Protein: 5 g
Fat: 7 g
Saturated Fat: 2 g
Cholesterol: 28 mg
Sodium: 331 mg
Sugar: 2 g
Reviews
Chrissy on 2018-10-01 (3 stars): Try vegan cheese!
Its dairy free. Or lactose free cheese.
Nicole on 2018-01-11 (5 stars): I love this recipe and make it all the time! I changed and/or omitted a few of the ingredients, though, to make the dish entirely plant-based. I use Vegenaise instead mayonnaise, Follow Your Heart's VeganEgg instead of a chicken's egg, and I completely omit the cheese. It's soooo good, and my version is cholesterol-free and much lower in fat and calories. Great recipe!
Ellie on 2018-01-04 (5 stars): I made this to use up some butternut squash I had hanging around. I wanted a change from the usual "sweet" recipes that use brown sugar or maple syrup with Thanksgiving-y spices.
I doubled the recipe, and split the difference between the parmesan and the cheddar - I mixed the parmesan in, but topped with cheddar. I also added a little thyme.
I thought it was delicious. Sadly, it did not win over the squash-hater in the family - but I'm not sure that anything would. Everyone else liked it, though!
It's a nice easy recipe, and I like the fact that it doesn't call for any exotic ingredient or a lot of complicated cooking. Just an easy way to make a tasty savory squash side dish.
Amanda Powers on 2015-11-22 (5 stars): Do you know if you can cook this in the slow cooker? We love this recipe but I am fighting for oven space this year.
