Pulse the butter and basil in a mini food processor about 30 seconds, until the basil is finely chopped and the mixture is creamy. Alternatively, chop the basil by hand and fold into the butter in a bowl. You’ll need just half the basil butter for this recipe. Cover and refrigerate up to a week. (It’s delicious on sweet corn, pasta or toasted bread).
Slice the squash into equal bite-size pieces. Bring 2 quarts of water to a boil with 2 tablespoons salt in a saucepan. Add the squash to the pan and set a timer for 3 minutes. Reserve 2 tablespoons of the cooking water, then immediately drain the squash.
Put ¼ cup of the basil butter in a serving bowl with 2 tablespoons of the cheese and ¼ teaspoon salt. Stir in 1 tablespoon of the reserved cooking water to make a creamy sauce. If your butter is cold you might need a little more water.
Toss the squash with the butter. Sprinkle with the rest of the cheese and serve.