Brown the butter. Add 1 tablespoon unsalted butter to a small saucepan over medium heat. Let it melt and bubble, stirring occasionally, until it turns golden brown and smells nutty, 3–5 minutes. Watch closely so it doesn’t burn.

Strain if needed. If you prefer a smoother latte, pour the brown butter through a fine mesh strainer to catch any dark bits. Keep the flavorful golden specks if you like extra toasty notes.

Warm the milk. In a separate pot (or the same pot after removing the butter), gently heat 6–8 ounces of milk until steaming but not boiling. Aim for around 150–160°F. Avoid scalding.

Emulsify the butter into the milk. Whisk the brown butter into the warm milk until fully combined, or use a handheld frother or blender for a creamy, uniform texture. Add a tiny pinch of salt to round out the flavors.

Pull your espresso. Brew 1–2 shots of espresso. If you don’t have an espresso machine, use strong coffee made with an Aeropress, Moka pot, or a concentrated pour-over.

Sweeten and flavor. Stir in 1–2 teaspoons of your preferred sweetener and a few drops of vanilla extract if using. Adjust to taste.

Assemble the latte. Pour the espresso into a mug. Top with the brown butter milk, holding back foam with a spoon, then spoon the foam over the top.

Finish and serve. Dust lightly with cinnamon or nutmeg if you like. Sip while warm for the best texture and flavor.