Butternut Squash Grilled Cheese with Caramelized Onions
The fall comfort food combination you didn’t know you were missing, until now!
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This butternut squash grilled cheese is inspired by a toast served at Jean-Georges Vongerichten’s ABC Kitchen in New York. I ate at the restaurant years ago and the transformation of squash stuck with me. Creamy roasted butternut squash is mashed with sweet caramelized onions finished with maple syrup to enhance the sweet and savory flavors while a splash of vinegar adds the perfect amount of acidity. It’s piled onto sourdough and paired with aged white Cheddar melted between perfectly golden bread. The sweet-savory-tangy balance is what makes this sandwich so distinctive (and so much more interesting than a standard grilled cheese!).
If you are a fan of an elevated grilled cheese I recommend trying my Tomato Bacon Jam Grilled Cheese or Sweet and Spicy Grilled Cheese Sandwich.
Why You’ll Love This Recipe
- Warming fall flavors. Butternut squash is at its peak in fall and early winter, and one of the best ways to use it is in combination with caramelized onions in this comforting sandwich.
- Restaurant-quality flavor, home cook effort. The squash and onion filling is a riff on a signature toast at Jean-Georges Vongerichten’s ABC Kitchen for a flavor that is sweet, savory, slightly tangy, and deeply rich all at once.
Key Ingredients in This Recipe
- Butternut squash – For the best butternut squash look with one that feels heavy for it’s size with uniform beige color skin. The nutty flavor of the roasted squash makes for a perfect fall filling.
- Onions – Yellow onions have a balance of natural sugars that break down for a balanced sweet and savory flavor when caramelized. For a deeper dive into the technique, see my how to caramelize onions guide.
- Apple cider vinegar – The acid from the vinegar is used to balance the flavor of the caramelized onions.
- Maple syrup – A bit of maple syrup adds a natural sweetness.
- Sourdough – The tangy flavor of the bread balances the rich cheese.
- Cheddar cheese – I love the tangy flavor that an aged white Cheddar adds to this sandwich. Shredding the cheese rather than slicing it, allows it to melt easier.
- Mayonnaise – Mayonnaise has a higher smoke point than butter and will create a golden brown crust on the grilled cheese.
- Butter – I melt butter in a pan to cook the grilled cheese. Combined with the mayo, it makes for a perfectly crisp grilled cheese with a buttery flavor.
A full ingredient list with exact amounts can be found in the recipe card below.
Swaps and substitutions
- Cheese: Other varieties of Cheddar can be used like medium white or yellow Cheddar which has a lower melting point or melty cheeses like fontina or Gouda.
- Squash: The butternut squash can be swapped for another variety like pumpkin or kabocha squash.
- Bread: Try swapping with classic white sandwich bread for a softer sandwich.
- Meat: Slices of thick cut bacon offer a salty and more filling combination.
Tips for the Best Butternut Squash Grilled Cheese
- Use both mayo and butter. Spread mayonnaise on the outside of each slice of bread before it hits the pan to create a deeper, more even golden crust than it would from just butter alone.
- Cook low and slow. Cooking over a medium-low heat ensures the cheese melts at the same rate the bread browns. Too high and you get a crispy exterior with an unmelted center. If you need it to melt faster, toss an ice cube in the pan and cover it for just a minute to create steam to melt the cheese.
- Choose the right pan. Cast iron or non-stick gives you the most even heat distribution and a consistently golden crust.
How to Make Butternut Squash Grilled Cheese (Step-by-Step)
Preheat the oven to 425ºF ( 220ºC). Halve the squash and scoop the seeds out. Rub the squash with 3 tablespoons (26g) olive oil then season with salt and red pepper flakes and place cut-side down on a large baking sheet.
Roast until squash is extremely tender, about 45 minutes.
Heat the remaining olive oil in a large stainless steel or cast iron pan over medium heat. Add the onions in batches, tossing to coat in the oil . Cook, stirring occasionally, until they are soft and golden, about 20 minutes.
Add the apple cider vinegar and the maple syrup to the onions, stirring to combine. Continue to cook the onions until they start to break down, about an additional 10 to 15 minutes.
Let cool slightly then scoop the tender flesh into a bowl and combine with the caramelized onions. Mash the mixture with a potato masher or by using a fork until combined.
Thinly spread one side of each bread slice with mayonnaise. Heat a large skillet or griddle over medium-low heat, add butter and allow to melt.
Place half of the slices of bread, mayo-side down, on the pan or griddle. Divide the cheese evenly on top of the bread slices (about 4 ounces cheese per sandwich). Top each with ½ cup (70g) of the butternut squash mixture. Top each with a second slice of bread, mayonnaise side up.
When the underside is golden brown, about 3 minutes, use a spatula to flip the grilled cheese and continue to cook. Gently press down on the sandwich to encourage browning and continue to cook until the cheese has melted and the underside is golden brown, about an additional 3 minutes.
Remove to a cutting board and cut each sandwich in half. Repeat with remaining ingredients. Serve immediately.
If you like comfort food try these:
Tried it? Loved it? Tweaked it? Leave a review below and tell me how it went – I’m all ears (and always hungry).
Butternut Squash Grilled Cheese with Caramelized Onions Recipe
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Ingredients:
- 1 medium (2-pound) butternut squash or other yellow-fleshed squash
- 6 tablespoons extra-virgin olive oil, divided
- Kosher salt, as needed
- ¼ teaspoon red pepper flakes
- 1 large yellow onion, thinly sliced
- 2 tablespoon apple cider vinegar
- 3 tablespoons maple syrup
- 1 pound sharp white cheddar cheese, shredded
- 4 tablespoons mayonnaise, divided
- 4 tablespoons unsalted butter, divided
- 8 slices sourdough bread or white country bread
Instructions:
- Preheat the oven to 425ºF ( 220ºC). Halve the squash and scoop the seeds out. Rub the squash with 3 tablespoons (26g) olive oil then season with salt and red pepper flakes and place cut-side down on a large baking sheet.
- Roast until squash is extremely tender, about 45 minutes.
- Heat the remaining olive oil in a large stainless steel or cast iron pan over medium heat. Add the onions in batches, tossing to coat in the oil . Cook, stirring occasionally, until they are soft and golden, about 20 minutes.
- Add the apple cider vinegar and the maple syrup to the onions, stirring to combine. Continue to cook the onions until they start to break down, about an additional 10 to 15 minutes.
- Let cool slightly then scoop the tender flesh into a bowl and combine with the caramelized onions. Mash the mixture with a potato masher or by using a fork until combined.
- Thinly spread one side of each bread slice with mayonnaise. Heat a large skillet or griddle over medium-low heat, add the butter and allow to melt.
- Place half of the slices of bread, mayo-side down, on the pan or griddle. Divide the cheese evenly on top of the bread slices (about 4 ounces cheese per sandwich).
- Top each with ½ cup (70g) of the butternut squash mixture. Top each with a second slice of bread, mayonnaise side up.
- When the underside is golden brown, about 3 minutes, use a spatula to flip the grilled cheese and continue to cook. Gently press down on the sandwich to encourage browning and continue to cook until the cheese has melted and the underside is golden brown, about an additional 3 minutes.
- Remove to a cutting board and cut each sandwich in half. Serve immediately.
Notes:
Tips for the Best Butternut Squash Grilled Cheese
- Use both mayo and butter. Spread mayonnaise on the outside of each slice of bread before it hits the pan to create a deeper, more even golden crust than it would from just butter alone.
- Cook low and slow. Cooking over a medium-low heat ensures the cheese melts at the same rate the bread browns. Too high and you get a crispy exterior with an unmelted center. If you need it to melt faster, toss an ice cube in the pan and cover it for just a minute to create steam to melt the cheese.
- Choose the right pan. Cast iron or non-stick gives you the most even heat distribution and a consistently golden crust. Avoid stainless steel — it creates hot spots and uneven browning.
Nutrition:
Calories: 1246kcal | Carbohydrates: 82g | Protein: 41g | Fat: 85g | Saturated Fat: 34g | Polyunsaturated Fat: 11g | Monounsaturated Fat: 30g | Trans Fat: 0.5g | Cholesterol: 149mg | Sodium: 1608mg | Potassium: 326mg | Fiber: 3g | Sugar: 17g | Vitamin A: 1559IU | Vitamin C: 2mg | Calcium: 897mg | Iron: 5mg
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