In a medium saucepan, combine granulated sugar, unsalted butter, milk, unsweetened cocoa powder, and a pinch of salt. Place the saucepan over medium heat and stir the mixture continuously until the butter is fully melted and everything is well combined, typically taking about 3–5 minutes.

Once melted, increase the heat slightly until the mixture comes to a rolling boil. Stir constantly and let it boil for exactly 1 minute.

Remove the saucepan from the heat and gently fold in the quick-cooking oats until fully coated with the chocolate mixture.

Stir in creamy peanut butter and vanilla extract until everything is well blended.

If using, fold in chopped walnuts or pecans ensuring they're evenly distributed.

Dollop generous spoonfuls of the mixture onto a wax paper-lined baking sheet.

Let the cookies set at room temperature for at least 30 minutes or in the refrigerator for a quicker setting time.

Once set, transfer the cookies to an airtight container for storage.