Roasted Acorn Squash With Caramelized Red Onions and Honey-Date Vinaigrette

Come fall and winter, well after juicy tomatoes have faded from market stands, winter squashes step into the spotlight to become a star ingredient in many kitchens. Although butternut squash gets more attention, acorn squash really deserves a place on your dinnertime roster—with its edible green exterior and nutty, sweet orange flesh, it’s beautiful on the plate and pairs wonderfully with plenty of other vegetables. It’s also mild enough to serve as an almost-blank canvas for a wide range of flavors, such as the sweet and tangy date-orange dressing it’s paired with in the recipe we’re sharing here from our Birmingham, Alabama-based test kitchen colleague Elizabeth Mervosh. 

For this autumnal side, wedges of the sweet, creamy squash are paired with thick slices of jammy, caramelized roasted red onion, then drizzled with an orange juice– and honey-tinged vinaigrette that’s studded with dates, and finished with crunchy pistachios. The playful combination of fall flavors is not only delicious, but sure to be the most talked about dish at your next holiday gathering. (Sorry, mashed potatoes!)

In developing this recipe, it was important for us that the roasted acorn squash and onions have a tender and moist interior and sweet caramelization on the exterior—we didn’t want any dry and burnt or soggy, undercooked, and tough squash and onions. To achieve the ideal texture on both vegetables, Elizabeth roasted batch after batch of acorn squash and onions and came up with this clever roasting method that ensures tender, perfectly browned vegetables every time.

Key Techniques for Perfectly Roasted Acorn Squash With Onions

Cut the vegetables to an even thickness. Cutting the squash and the onions into similarly-sized wedges not only ensures an attractive presentation, but it also promotes even cooking. We found it easier to cut the squash crosswise (against the ridges of the squash) rather than along the ridges, which—bonus!—also shows off the squash’s attractive fluted sides. And don’t bother attempting to peel the squash; its natural ridges make that almost impossible. Just roast it with the skin on—it’s typically thin enough to eat, but if you prefer it without the skin, the meat of the squash will peel away easily from the skin once the squash is roasted.

Roast the onions and squash on separate baking sheets. Elizabeth realized early on in her testing that the onions and squash cooked at different rates. Cooking them together was a recipe for undercooked crunchy onions with tender squash, or perfectly cooked onions with mushy overcooked squash. The solution? Roasting them on separate sheet trays, which ensures the squash is tender and the onions soften evenly.

Arrange vegetables along the perimeter of the sheet pan for even roasting. Roasting on separate sheet trays still wasn’t enough to guarantee evenly browned and properly cooked vegetables. When the vegetables were just randomly scattered over the trays, they browned OK, but the browning wasn’t consistent: The slices on the edges of the pan were over-browning, while the slices in the center of the sheet were still pale. By arranging the squash and onion slices evenly around the perimeter of the baking sheet and avoiding the middle of the pan altogether, then rotating the sheet halfway through roasting, all of the slices browned well. 

Start by steaming the onions. A common problem with roasting onions is that their outer layers can dry out and turn leathery before the interior petals are tender and the bottoms well browned. We wanted roasted onions that were soft and juicy from top to bottom. To get around this problem, we started by covering the pan of onions tightly with aluminum foil, roasting them briefly—just 10 minutes—then uncovering them and letting them finish roasting while the squash cooks on the bottom rack. Covering the onions traps in their steam, and that steam is a powerful cooking medium that softens the onion’s outer layers, ensuring that the exterior peels won’t dry out.

Jumpstart the squash’s browning by preheating the baking sheet. While placing the squash around the perimeter of the sheet tray ensures even cooking, our testing showed that even when we cranked the heat up and baked the squash on the lowest oven rack (closest to the heat source), the bottom cut sides of the squash were still not getting as browned as we wanted them. The solution was fairly simple: Preheating the baking sheet before quickly arranging the squash on the hot sheet to roast, which helped greatly with browning. Once the squash hits the pan, it starts searing immediately.

Once your vegetables are roasted, all that’s left is to whisk together a punchy vinaigrette that’s enhanced with sweet orange juice, honey, and dates with a hint of heat from chile powder. Then this fall side is ready for its close-up.

November, 2024