Line a baking sheet with parchment paper. Set aside.
In a small saucepan over medium-low heat, melt butter. Swirl pan every 30 seconds until butter begins to sizzle. Reduce heat to low. Continue swirling for ~3 minutes or until melted butter becomes foamy, makes popping sounds, and begins to take on a nutty aroma! Mixture will begin to turn golden brown and have brown flakes interspersed. Using a wooden spoon or spatula stir butter, lift browned butter bits from the bottom of the pan. Remove from heat and allow to cool. In the meantime, move onto step 3.
In a small bowl, whisk together flour, baking soda, and salt. (This process aerates and sifts dry ingredients!) Set aside.
Using a large bowl with an electric mixer or the bowl of a stand mixer, beat sugars (brown and granulated) with melted brown butter and heavy cream for 1 min. Add in egg and vanilla extract. Stir until combined and scrape sides of bowl once more to incorporate all the batter.
Slowly add flour mixture to the wet butter/sugar/egg mixture, beating on low speed until just combined. Add roughly chopped white chocolate pieces and macadamia nuts to the batter. Mix together until combined.
Scoop dough into 2 tbsp portions and set on flat plate/baking sheet.
Refrigerate dough for at least 1h (note: this step allows all of the beautiful cookie flavours to combine and form a perfectly spread cookie!)
Preheat oven to 350F (325F if using convection bake).
Once dough is chilled, remove from fridge and place cookies onto baking sheet, spaced 2" apart (Note: to give these cookies that perfect bakery texture - tear them in half and place the torn side of one half on top of the other. Gently press into a small ball). Place a few additional pieces of white chocolate onto each cookie dough ball, as desired.
Bake cookies for 14-15 min or until the edges are golden brown.
Sprinkle each cookie with flaked salt upon removing from the oven! Allow to cool on cookie sheet until easy to pick up (5-10 min) then finish cooling on cookie rack.
Enjoy!!