Melt butter in an 8-inch cast iron skillet over low heat. Remove from heat.
Add sugars
Stir in brown sugar and cane sugar until smooth and glossy.
Add egg and vanilla
Stir in egg and vanilla until fully incorporated.
Add dry ingredients
In a small bowl, whisk together flour, baking soda, and salt.
Stir into the skillet just until combined. Do not overmix.
Fold in mix-ins
Gently fold in white chocolate chips and chopped macadamia nuts.
Smooth the top evenly.
Bake at 350°F for 10 minutes
(Sets the edges and surface)
Reduce oven to 325°F
Without removing the skillet, continue baking 12–15 minutes
Notes
Doneness Cues
Edges are set and lightly golden
Center looks matte, not shiny
Gentle jiggle in the center is OK
Remove from oven and let rest 10 minutes in the skillet before serving.(The cookie continues to set as it rests.)
Side Note — Optional Sourdough Variation
For a slightly more structured skillet cookie with subtle depth, you may add 2 Tbsp (30 g) sourdough discard and increase flour by 1 Tbsp (8 g). Bake 2–5 minutes longer.
Keyword date night, dessert, fresh milled, one pan, soft white, special occasion, whole grain