Preheat your oven to 350 degrees F. Place the squash directly on your oven racks and allow them to cook for 30 minutes. This will make it SO much easier to cut and peel them (totally worth this step). Once they’re cool enough to handle, cut the tough outer skin/peel away and slice in half. Remove the seeds and then cut the squash into small, roughly 1-inch pieces. 

Meanwhile, while the squash are roasting away, add the oil to a large, deep pot set over medium heat. Add the sliced onion and 1 tsp salt and cook, stirring frequently, until they have softened tremendously and turned a medium-brown color; about 25 minutes. We’re not fully caramelizing them here – it’s a light caramelization. 

Once the onions have cooked for about 25 to 30 minutes, add the squash into the pan with the onions along with ½ cup water and ½ tsp salt. Stir and cook, covered, for 5 minutes. Remove the lid, stir and mash up the squash and add another ½ cup water. Cover and cook for another 5 minutes. Transfer the mixture to a blender. Blend until totally creamy and smooth. Pour back into the pot.

Taste the mixture and add salt/pepper as needed. Add another 1 cup water and stir! Stir! Continue cooking the soup and adding water until you get it to a true pureed soup consistency (not thick baby food). You can determine the consistency that best suits your tastes here. The soup will reduce and thicken the longer you keep it over the heat, and also, if you get it too thin (if you add too much water), just let it cook a little longer. Serve as it is or with toppings of your choice such as toasted nuts, sliced apples, and maple syrup (pictured).