Melt butter in a small pan over medium heat (or in microwave). Cool slightly before using.
Add butter to a stand mixer bowl, along with brown and granulated sugars, vanilla extract, and salt. Mix until smooth and shiny (a couple minutes). Beat in egg.
Whisk together flour and baking powder in a separate bowl, then add to butter mixture. Mix until completely combined.
Add chocolate, cranberries, and walnuts to dough; mix well.
Roll heaping tablespoons of dough into balls and place on greased baking sheets about 2 inches apart. Using fingers, flatten balls slightly.
Refrigerate cookies for at least one hour.
Preheat oven to 375 degrees.
Bake cookies for 15 minutes or until browned on the bottom and lightly colored on top.
Let cookies cool for 5 minutes, then transfer to a baking rack to cool completely.
Store any cookies you don't eat right away in an airtight container. Enjoy!
Notes
Chilling the dough before baking helps give the cookies their thick and chewy texture. Don't skip this step.When measuring the flour, make sure to spoon it into the measuring cup until overflowing. Then level off the top with a knife (or another flat object).Check out the info before this recipe card for helpful tips, variations, related recipes, and more!