1 cup smooth peanut butter
1 1/4 cups whole milk, at room temperature
2 eggs at room temperature, beaten
2/3 cup granulated sugar
1 teaspoon kosher salt
2 teaspoons baking powder
1/2 teaspoon baking soda
1 1/2 cups all purpose gluten free flour
2 tablespoons cornstarch
1 1/2 to 2 ounces semi-sweet chocolate chips (optional)
1/2 cup chopped peanuts (optional)
Preheat your oven to 325°F. Grease or line a standard 9-inch x 5-inch loaf pan and set it aside.
In a large, heat-safe bowl, place the peanut butter. Microwave for 30-seconds on high power just to loosen up the peanut butter and make it easier to stir. Remove it from the microwave and whisk the peanut butter until smooth. Add the milk, eggs, sugar, salt, baking powder and baking soda, whisking to combine well after each addition. The batter will be thin. Switch to a large spoon or spatula, and add the flour and cornstarch, mixing to combine after each addition. The batter will be relatively thick. Scrape the batter into the prepared loaf pan, and smooth the top with a wet spatula. Using a very sharp knife, score the center of the loaf along the length from one end to the other in one swift motion. Scatter the (optional) chocolate chips over the top of the batter, and press the chips gently into the batter to adhere.
Place the pan in the center of the preheated oven and bake until a toothpick inserted in the center comes out with a few moist crumbs attached (about 1 hour), rotating once during baking. Remove from the oven and allow to cool in the loaf pan for 15 minutes before turning out onto a wire rack to cool completely. Slice thickly and serve with jam, jelly or preserves. Wrap any leftover slices tightly in freezer-safe wrap and freeze until ready to use. Defrost at room temperature.