Combine squash, 1/4 cup butter, and salt in a saucepan over medium heat; cook and stir until heated through and butter is melted, about 5 minutes. Mix eggs into squash mixture until thoroughly combined; pour into a 1-quart casserole dish.
Mix brown sugar, pecans, 3 tablespoons butter, and cinnamon together in a bowl; sprinkle over squash mixture.
Bake in the preheated oven until bubbling, about 30 minutes.
