Roasted Butternut Squash Sandwich with Caramelized Onions and Pesto

Disclosure: Delightful Plate is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. We only recommend products we use and trust.

This roasted butternut squash sandwich with caramelized onion and pesto is a super easy recipe to make when winter squash is abundant. It is excellent for a healthy meatless lunch or dinner.

a slice of roasted butter squash sandwich with caramelized onions and pesto

This recipe is my version of the sandwich I used to love at a store near my old workplace. Nowadays, I enjoy making it at home (besides this pumpkin soup and pumpkin fritters with salted egg yolk sauce) when winter squash is in season. It is easy to make, and there are several ways to customize it to your liking.

Ingredients

Here are the main ingredients you’ll need for this recipe:

  • butternut squash: I haven’t tried making this sandwich with other types of cooking squash. If you try other squashes, please feel free to comment.
  • bread: I often use ciabatta. Baguette, hoagie roll or your other favorite bread for sandwich will work too.
  • caramelized onions: these are sliced onions that are cooked on the stove gradually until caramelized, soft and sweet.
  • pesto: it adds a pleasant herby fragrance to the sandwich. If you want to keep the sandwich vegetarian/vegan, please use vegetarian/vegan pesto.
plates with sliced butternut squash and onions

Optional Add-ins

You can customize this roasted butternut squash sandwich by adding more filling, for example:

  • cheese
  • arugula
  • other roasted veggies such as zucchini or eggplant

Main Cooking Steps

The recipe has two main steps, which are not quick but fairly straightforward.

1️⃣ Roasting the butternut squash: simply slice the squash thinly, and toss with salt, pepper and oil. You can also add some dried herbs if desired. Then bake in the oven until tender.

a baking sheet with butternut squash slices
roasted butternut squash slices on a baking sheet

2️⃣ Caramelizing the onions: this step does require some time and patience. You will need to cook the onions gradually to deepen the color, flavor and sweetness. 

I like to start with cooking the onions in olive oil over medium heat, and then reduce the heat as needed. Halfway through the process, time to add some butter and continue to cook until your desired level of caramelization is reached.

adding onion slices to a skillet
cooking onion slices in the skillet
caramelizing onions in the skillet

I don’t think it is necessary to cook them very dark. I prefer a lighter level of caramelization which ensures no unpleasant bitterness as well as saves up some cooking time.

Once these two components are ready, you can assemble the sandwich pretty quickly. I like to have the bread toasted for some extra crunch. I look forward to hearing how you make this roasted butternut squash sandwich recipe.

If you need more some fun ideas for what to make with bread, also give these baked shrimp toast and slow cooker pulled pork banh mi a try.

a tray of roasted butternut squash sandwiches with salad on the side

⭐️ I’d love to hear what you think about the dish, so please feel free to leave a comment and a rating if you have tried it. New recipes are added every week so let’s connect on FacebookYoutubePinterest and Instagram for the latest updates. You can find my collection of Vietnamese recipes here.

a plate of roasted butternut squash sandwiches with pesto

Roasted Butternut Squash Sandwich with Caramelized Onions and Pesto

This roasted butternut squash sandwich with caramelized onion and pesto is a super easy recipe to make when winter squash is abundant. It is excellent for a meatless lunch or dinner.
Author: Sophie
5 from 3 votes
Prep: 10 minutes
Cook: 50 minutes
Total: 1 hour
Servings: 2 people

Ingredients
 

  • 18 oz peeled and thinly sliced butternut squash (no more than ¼ inch thick)
  • 1/2 plus 1/8 teaspoon salt, divided
  • 3/8 teaspoon black pepper, divided
  • olive oil
  • 2 yellow onions, peeled and thinly sliced (about 10.5 oz/300g)
  • 1 tablespoon butter
  • your choice of bread for sandwich
  • 2-4 tablespoons pesto

Instructions
 

  • Preheat the oven to 425°F (220°C). Toss the butternut squash slices with teaspoon salt, ¼ teaspoon pepper and tablespoons olive oil. Arrange them in a single layer on a baking sheet lined with parchment paper.
  • Roast the butternut squash in the preheated oven for about 20 minutes, then flip and roast until tender and browned to your liking, about 10 minutes more.
  • Place a skillet over medium heat and add oil to coat the bottom. Once the oil is hot, add the onion slices. Let them cook, stirring occasionally for about 15 minutes. Reduce the heat if needed.
  • Add the remaining salt and pepper to the onions, stir and cook for another 5 minutes. Increase the heat back to medium, then add butter. Continue to stir and cook for 20-30 minutes more until they are browned, soft and sweet. A light degree of caramelization will also work.
  • Toast the bread. Spread pesto on each cut side, then add the roasted butternut squash slices and caramelized onions. See Notes for optional add-ins. Serve right away.

Notes

You can customize this roasted butternut squash sandwich by adding more filling, such as:
  • cheese
  • arugula
  • other roasted veggies such as zucchini or eggplant
You can use ciabatta, hoagie rolls, baguettes or your other favorite bread for sandwich.

Nutrition

Calories: 332kcal | Carbohydrates: 55g | Protein: 7g | Fat: 12g | Saturated Fat: 5g | Polyunsaturated Fat: 0.3g | Monounsaturated Fat: 2g | Trans Fat: 0.2g | Cholesterol: 16mg | Sodium: 1064mg | Potassium: 1066mg | Fiber: 8g | Sugar: 11g | Vitamin A: 27604IU | Vitamin C: 62mg | Calcium: 176mg | Iron: 2mg
Course: Appetizer, Main Dish
Cuisine: American
Keyword: butternut squash sandwich
Tried this recipe?Comment & Rate below or Tag @delightfulplate on Instagram
Liked our videos?Subscribe to our Youtube channel and cook along with us

Similar Posts

4 Comments

  1. 5 stars
    Love the flavors here, but next time I’m going to try with my homemade cranberry sauce for a bit of tart flavor!

    1. Hi Bonny,
      Thank you so much for the positive feedback and rating! So glad you also love the flavors. Using cranberry sauce sounds like a great idea. I often add dried cranberries whenever I have roasted butternut squash salad. Please feel free to let me know how the sandwich tastes with cranberry sauce :).

Leave a Reply

Your email address will not be published. Required fields are marked *

Recipe Rating