Preheat your oven to 325°F. Line a rimmed baking sheet with unbleached parchment paper and set it aside.

In a large bowl, place the whey protein isolate, cornstarch, and baking soda, and whisk to combine.

Add the peanut butter, honey, egg and egg yolk, and optional vanilla, and mix just until combined.

Add the miniature chocolate chips, and mix until they’re evenly distributed throughout the cookie dough. The mixture will be thick but very soft, and if you continue to mix after it’s combined, it tends to become oily.

Using a large spring-loaded ice cream scoop (mine is equivalent to a #24 and holds 3 tablespoons in volume), divide the dough into 8 roughly equal portions.

Place the portions about 1 1/2-inches apart from one another on the prepared baking sheet. Using wet fingers, pat into a disk about 1/2-inch thick.

Place the baking sheet in the center of the preheated oven and bake for about 12 minutes, or until lightly golden brown all over, darker toward the edges and set in the center. When the cookies are set in the center, the dough will no longer glisten.

Remove from the oven and allow to cool briefly before serving.

Once cool, the cookies can be piled into a freezer-safe bag and frozen. Defrost briefly before serving.