Preheat the air fryer to 325°F by running it for 2-3 minutes before baking. Prepare the air fryer baking pan or basket by lining with a sheet of parchment paper. Set aside.
In a large bowl, whisk together 12 tablespoons unsalted butter (melted), ¾ cup brown sugar, 1 tablespoon maple syrup, 1½ teaspoons vanilla extract and 2 egg yolks until smooth and uniform in color.
Add 2 cups all-purpose flour, ½ teaspoon baking soda and ¼ teaspoon sea salt directly to the wet ingredients in the bowl. Use a spatula to mix until everything is just combined; do not over-mix. It will be soft at first but will stiffen as it sits.
Mix in 1 cup semi-sweet chocolate chips (and any other add-ins) until they are well-distributed.
Using a small spring-loaded cookie scoop, scoop dough balls onto prepared pan or basket, leaving about 2 inches between each. (See notes about amount for each air fryer.)
Place the pan or basket in the air fryer. Set the air fryer to "Bake" and bake for 325°F for 7-9 minutes. (Times will vary depending on air fryer and how you like your cookies; see notes.)
When the air fryer is finished baking, remove the pan or basket from the air fryer and let the cookies remain on the parchment for about 5 minutes, allowing them to set and slightly harden as they will be soft and difficult to move when warm.
Use a spatula to remove cookies once set and let cool completely on a baking rack.