Step 1

Arrange a rack in the middle of the oven and heat to 350°F. Lightly coat a 9-x9-inch square baking dish with olive oil or butter.

Step 2

Peel the bananas and mash their flesh in a medium bowl. Mash very thoroughly until no large chunks remain; the bananas should be essentially liquid. (You will have between 1 and 1 1/4 cups.) Stir in the vanilla, if using. Add the oats and stir them in. Stir in the dates, nuts, and salt.

Step 3

Transfer to the baking dish and pat into an even layer. If desired, sprinkle the top lightly with nutmeg or cinnamon. Bake until the edges just begin to crisp up, about 30 minutes.

Step 4

Place the baking pan on a rack to cool. Meanwhile, if you’re making the glaze, whisk together the yogurt, honey, powdered sugar, and milk in a small bowl. When the pan is cool, cut into 9 squares. Drizzle each square with the glaze and enjoy.