A perfectly designed chocolate chip cookie to me means a gooey center and lightly crisp edges. This cookie takes the “gooey center” part literally by having a vegan marshmallow tucked inside the center of each one. Since vegan marshmallows aren't made with gelatin, they stay fluffy throughout baking.
Position the racks in the upper and lower third of the oven and preheat to 375 degrees F. Line two rimmed baking sheets with parchment. (If you only have one baking sheet, let it cool completely between batches.)
Place the butter in a small microwave-safe bowl, cover and microwave on medium power until melted, 1 to 2 minutes. (Alternatively melt in a small saucepan.) Cool slightly.
Whisk the dark brown sugar, granulated sugar, eggs, melted butter and vanilla in a large bowl until smooth.
Whisk the flour, baking soda and salt in a medium bowl. Stir the dry ingredients into the wet ingredients with a wooden spoon, taking care not to overmix. Stir in the chocolate chips.
Use an ice cream scoop or measuring spoon to scoop out portions of dough (each about 3 tablespoons or 2.2 ounces). Flatten each portion in the palm of your hand until it’s about 1/4-inch thick. Place 1 marshmallow in the center of the flattened dough and form the dough around the marshmallow until it is completely covered. Roll into a uniform ball and place about 2 inches apart on the prepared baking sheets. Bake until the edges and top are just turning golden, but the center is still soft, 17 to 18 minutes.
Let the cookies cool slightly on the baking sheets, about 5 minutes. Serve warm.
When measuring flour, we spoon it into a dry measuring cup and level off excess. (Scooping directly from the bag compacts the flour, resulting in dry baked goods.)