Southern Squash Casserole

Ingredients

• kosher salt
  
• 3 pounds summer squash
  
• 6 tablespoons unsalted butter, melted and divided
  
• 1 1/2 cups diced onions
  
• 1/2 cup whole milk, at room temperature
  
• 2 large eggs, at room temperature
  
• 1 to 2 teaspoons sugar (optional)
  
• 1/2 cup cracker crumbs
  

Directions

1. Bring a large pot of water to boil and add 1 tablespoon kosher salt per quart. Chop squash into 1-inch pieces and boil until tender, but not mushy, about 5 to 7 minutes.
2. Melt 4 tablespoons butter in a pan and sautée onions until soft, 5 to 7 minutes. Set aside to cool.
3. Drain squash well and rinse under cold water. Set on a dish towel to dry. Preheat oven to 450° F and butter a 9- by 11-inch baking dish.
4. Whisk together milk, eggs, and 1 teaspoon salt. Add 1 to 2 teaspoons sugar if you are using poor quality (or out of season) squash.
5. Layer squash and buttered onions in a baking dish and pour milk mixture over it. Top with cracker crumbs (I am partial to cheese crackers, but Ritz crackers are the traditional choice), and drizzle remaining 2 tablespoons butter over top.
6. Bake for 20 minutes, or until custard is set. Let cool about 10 minutes before serving.