Oatmeal Peanut Butter Cookies with Chocolate Chips

In a large microwave-safe mixing bowl, melt the butter.
Add the peanut butter, sugar, egg, salt, and vanilla. Stir the wet ingredients until smooth.
Sprinkle the flour, baking soda, baking powder, and cornstarch over the wet ingredients. Mix well to combine everything into a soft dough.
Add the oats and the chocolate chips. Mix again until they are evenly incorporated.
Chill the dough for 30 minutes. While chilling, preheat the oven to 350°F. Line two sheet pans with parchment paper.
Scoop or spoon portions of the dough to make 24 equal balls about 28g each. Space them out on the two sheet pans.
Bake for 14-15 minutes, until the edges start to turn golden brown. Swap the pans from top to bottom halfway through the baking for even cooking and browning.
If the cookies have crowded into one another during baking, use a biscuit cutter or drinking glass to swirl the baked cookies into separate, rounded cookies right on the baking pan.
Allow the cookies to sit on the pan for 3-4 minutes before transferring them to a wire rack to cool completely.