Position a rack in the center of the oven and heat the oven to 375°F. Grease a deep 9- or 10-inch pie plate (with a capacity of at least 6 cups) with olive oil.
In a small bowl, combine the lime juice, lime zest, brown sugar, coriander, cumin, chipotle powder, and 1/4 tsp. salt.
In a medium bowl, coat the squash with the olive oil. Add the spice mixture and toss to coat. Spread in a single layer in a small roasting pan or on a rimmed baking sheet. Wrap the garlic cloves in aluminum foil. Roast until just tender, about 20 minutes for the squash and 40 minutes for the garlic. Squeeze the garlic out of the skins into a small bowl and mash with a fork.
Lower the oven temperature to 350°F.
Put the crumbled cornbread in a medium bowl. Add 1/4 cup plus 2 Tbs. of the milk, and stir to combine. Press into the bottom and up the sides of the pie plate. Pierce the bottom several times with a fork. Bake until the crust is deep golden, about 15 minutes.
In a small bowl, mash the beans and 1 Tbs. water with a fork. Season to taste with salt, and spread in the bottom of the crust, using wet fingers to press down evenly. Place the pie plate on a baking sheet.
Whisk the remaining 1-1/2 cups milk and the eggs in a large bowl. Fold in the roasted garlic, squash, cheese, scallions, and 1/2 tsp. salt. Pour into the crust.
Bake until the top is browned and a toothpick inserted in the center comes out clean, about 1 hour. Cover the crust with aluminum foil or a pie shield if it starts getting dark.
Cool on a rack for at least 1 hour before slicing. Serve warm or at room temperature.
nutrition information (per serving):
380, Fat Calories
22, Saturated Fat
12, Polyunsaturated Fat
2, Monounsaturated Fat
Photo: Scott Phillips