In a medium saucepan, combine 1/2 cup of milk, 1/2 cup of unsweetened cocoa powder, 1/2 cup of honey (or maple syrup), and 1/2 cup of natural peanut butter. Heat over medium heat, stirring continuously for about 5–7 minutes until the mixture is smooth and well-combined.

Remove the saucepan from heat and quickly stir in 3 cups of old-fashioned oats and 1 teaspoon of vanilla extract. Mix thoroughly until the oats are evenly coated and the mixture appears thick.

Using a spoon or cookie scoop, drop spoonfuls of the mixture onto a lined baking sheet or parchment paper. Flatten each scoop slightly into cookie shapes, spacing them about an inch apart.

Place the baking sheet in the refrigerator for about 30 minutes or until the cookies are firm and set.

Once set, serve the cookies straight from the fridge or store leftovers in an airtight container in the refrigerator for up to a week.