Brown the butter

• Melt the butter in a saucepan over medium-high heat, stirring continuously.
• Keep cooking until it foams, the milk solids turn brown and the color deepens to a deep golden amber with a nutty smell.
• Immediately pour into a large bowl and set aside to cool slightly so it doesn't melt the sugars.

Cool the brown butter

• Let the brown butter cool enough that it won't melt the sugars when added, which keeps the cookies from spreading too much.
• Meanwhile, line a baking sheet with parchment paper.

Mix the dry ingredients

• In a separate medium bowl, whisk together the flour, baking soda, baking powder and salt.

Make the wet mixture

• Add both sugars to the cooled brown butter and whisk until well combined.
• Add the eggs and whisk until lighter in color.
• Add the heavy cream and vanilla and whisk until well combined; the mixture should look and smell like caramel.

Combine and add chocolate

• Add the dry ingredients to the wet and gently fold until just combined.
• Add the chocolate chips and chunks and gently fold until evenly dispersed.

Scoop and chill the dough

• Scoop the dough onto the lined baking sheet with a large cookie scoop, packing it with your hands, each ball weighing about 83-85 g.
• Cover with plastic wrap and refrigerate for at least 3-4 hours, ideally overnight or up to 48 hours.

Preheat the oven

• Preheat the oven to 375 °F and line a large baking sheet with parchment paper.

Bake the cookies

• Space the cookies about 2 inches apart on the baking sheet, about 5 at a time.
• Bake until the centers are slightly puffed and lightly golden and the edges are golden and set; they should look almost underbaked.
• If needed, immediately shape the hot cookies into perfect circles with a bowl or round cutter and press extra chocolate chips on top.

Cool and serve

• Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire cooling rack.
• Serve warm with a sprinkle of flaky sea salt and a cold glass of milk.