Squash refers to numerous members of the gourd family divided into two categories – summer and winter. Summer squash, such as zucchini and crookneck, have thin, edible skin, soft flesh and a mild flavor. Winter squash, such as butternut and acorn, have thick skin, dark flesh and a stronger, concentrated flavor. Squash responds well to several cooking methods, including boiling and roasting. Boiled squash has several applications in purees, soups and baked goods, and roasted squash is commonly used as a side dish.
Cut the squash in half, remove the seeds and place it cut-side-up on a sheet pan. Rub the cut surfaces of two halved lemons over the flesh to prevent oxidation. Preheat the oven to 400 degrees Fahrenheit.
Coat the cut sides and the inside of the seed cavity of the squash with olive oil and season to taste with kosher salt and freshly ground black pepper. Add any seasonings that contain large amounts of sugar, such as brown sugar, honey and maple syrup, in the last 15 minutes of cooking – sugar burns quickly at roasting temperatures, and caramelizes before the squash finishes cooking. Place the squash cut-side-down on a sheet pan.
Roast summer squash for 30 minutes and winter squash for 45 minutes, or until the skin blisters and the flesh softens.
Cut the squash in half and remove the seeds.
Peel the skin from the squash and cut into one-inch cubes. Add the squash to a pot, cover with cold water or chicken stock and season to taste with kosher salt. Do not add the squash to boiling water or stock—the abrupt temperature change "shocks" the starch and results in a mealy consistency.
Boil the squash until fork tender and reserve the liquid. Allow the squash to cool and place in a food processor. Pulse the squash until it has a smooth consistency, adding the remaining cooking liquid as needed to facilitate pureeing.