Step 1: Create the Brown Butter
Cut the butter into tablespoons and place it in a light-colored saucepan (so you can see the color change) over medium heat. Melt the butter, then continue to cook, swirling the pan occasionally. It will foam and crackle. After 3-5 minutes, the crackling will subside, and you’ll see golden brown specks form at the bottom. It will smell nutty and toasty. Immediately remove from heat and pour into a heatproof bowl to stop the cooking. Set aside.

Step 2: Craft the Caramel
Carefully wipe the same saucepan clean. Add the granulated sugar in an even layer over medium heat. Do not stir. The sugar will begin to melt around the edges. You can gently swirl the pan to ensure even melting. Continue cooking until the sugar has completely liquefied and turned a deep amber color.

Step 3: Combine Butter and Caramel
Once the sugar is amber, reduce the heat to low. Slowly and carefully whisk in the brown butter. The mixture will bubble vigorously. Whisk until it is completely smooth and integrated.

Step 4: Incorporate the Cream
Slowly drizzle in the warmed heavy cream while whisking constantly. Again, the mixture will bubble up. Whisk until the caramel is smooth and uniform.

Step 5: Finish the Syrup
Remove the saucepan from the heat. Whisk in the vanilla extract and the ½ teaspoon of flaky sea salt. Let the syrup cool for about 15 minutes before transferring to a jar. It will thicken as it cools.

Step 6: Assemble the Latte
Fill a tall glass to the brim with ice cubes. Drizzle 1-2 tablespoons (or more to taste) of the cooled brown butter caramel syrup over the ice.

Step 7: Pour the Coffee and Milk
Pour the chilled coffee or espresso over the ice. Then, top the glass with your milk of choice.

Step 8: Garnish and Serve
For a decadent finish, top with a dollop of whipped cream, an extra drizzle of the caramel syrup, and a final, crucial pinch of flaky sea salt. This salt enhances every flavor. Serve immediately with a straw and stir thoroughly to combine all the layers