Preheat your oven to 350 degrees. Line a baking sheet with parchment paper.
Combine the cooled, melted butter, brown sugar, white sugar, and vanilla extract in the bowl of a stand mixer. Beat until creamy.
Beat in the egg yolk until the mixture looks glossy.
Combine the flour, baking soda, baking powder, and salt in a small bowl until mixed well.
Gradually add it to the butter mixture. Fold it in until evenly combined.
Add most of the white chocolate chips and fold them in. Add most of the chopped fresh strawberries and fold them in gently. No need to be too gentle here–strawberries are quite sturdy. Mix them in well, and the moisture from the strawberries will soften the cookie dough, making it easier to scoop.
Scoop mounds of dough onto prepared baking sheets.
Bake for 15-20 minutes until golden brown. Side Note: These cookies take longer to bake due to the moisture of the strawberries.
Remove from the oven and immediately press a few more of the remaining diced strawberries and white chocolate chips onto the top of each cookie.
Let them cool for 3 minutes on the baking sheet, then transfer to a wire cooling rack to finish cooling.