Preheat your oven to 375°F (190°C) and position your racks in the center.

In a large mixing bowl, combine the unsalted butter, granulated sugar, and light brown sugar. Beat on medium speed for about 3 minutes until light and fluffy.

Add the beaten eggs and vanilla extract to the bowl. Mix on low speed until fully incorporated, approximately 1 minute.

In a separate bowl, whisk together the all-purpose flour, baking powder, baking soda, and fine sea salt.

Gradually add the dry mixture to your wet ingredients, mixing just until combined.

Gently fold in the old-fashioned rolled oats using a spatula.

Stir in the bittersweet chocolate chips, chopped Hershey's chocolate bars, and any chopped nuts.

Using a tablespoon or cookie scoop, portion the dough onto ungreased cookie sheets, spacing them about 2 inches apart.

Bake for 8-9 minutes until the tops are golden but remain soft. They will firm up while cooling.

Let the cookies cool on a wire rack for a few minutes before serving.