Place butter in a medium saucepan over medium heat, stirring often, until it foams, then browns, 5-8 minutes. The butter can burn easily after it foams so watch carefully and be prepared to take off the heat. Set aside and let cool.
In a mixing bowl, add your flour, baking soda, and kosher salt together and whisk until evenly combined. You can make espresso powder by grinding coffee beans and sifting it so it is extremely fine with no coarse pieces.
In your stand mixer or another mixing bowl, add sugars (brown and granulated) and browned butter together and beat on medium speed for about 1 minute until incorporated.
Add your eggs and vanilla and mix for another minute. The mixture should thicken and lighten at this point.
Reduce speed of stand mixer or electric hand mixer and add dry ingredients and beat just to combine. Mix in 3/4 of your chopped white chocolate and 3/4 cup of broken pretzels.
The dough will be quite soft so to hydrate the flour and allow to thicken. Place your dough on counter for 15 minutes.
Place a rack in the middle of the oven; preheat to 350°F. Scoop with 1/4 cup or ice cream scoop. These make about 10-12 large cookies or 20 smaller ones.
Top cookie dough ball with more pretzels and chopped caramelized white chocolate. Cookie dough will look crowded but cookies spread significantly and toppings will space out.
Bake cookies on a parchment lined baking tray until edges are golden brown and firm but centres are still soft, 13-15 minutes for larger cookies or 9-10 minutes for smaller cookies. Make sure you really spread out your large cookies. If I am making only 10 cookies, I can usually only fit a maximum of 3 cookies per baking sheet.
Your cookies should be golden brown and caramelized on the edges and crinkly, and just done in the middle a bit glossy (almost under done looking). You can top with even more broken pretzels like I like to do. You can lodge then gently into the pools of chocolate on top.
Leave your cookies to cool before enjoying so they firm up.
You can freeze the cookie dough and bake from frozen, adding more time when baking OR freeze your cookies after you have baked them and enjoy them frozen or thawed.
