Split the vanilla bean lengthwise if you are using one, and set the vanilla extract aside for later if that is your choice. The bean should be opened so its flavor can infuse the syrup while it simmers.

Combine the sugar, water, and vanilla bean in a small saucepan and bring it to a boil, then lower the heat and let it simmer for 5 minutes. The syrup should look clear and lightly thickened, not dark or sticky.

Cool the syrup completely, then remove the vanilla bean; if using vanilla extract, stir it in after the syrup has cooled from the simmer. The finished syrup should smell sweet and warm, with a clean vanilla aroma.

Place the brown sugar, butter, half-and-half, and salt in a small saucepan and stir over medium-low heat for 1 minute. The mixture should melt together into a smooth, glossy base.

Turn the heat down to low and let the sauce simmer for 10 minutes. It should thicken enough to coat a spoon but still pour easily.

Take the pan off the heat and let the sauce cool before using it. As it cools, it will become a little thicker and better for drizzling.

Add the vanilla syrup to the bottom of your mug. This gives the drink sweetness from the base so it blends gently into the milk.

Froth the milk in a separate container, then pour the milk and foam into the mug over the syrup. The top should look fluffy and thick enough to hold a slow pour of espresso.

Brew 1 shot of Starbucks® Espresso Roast by Nespresso®, then pour it slowly through the center of the foam. You should see a dark espresso mark settle over the pale foam instead of disappearing right away.

Finish with a drizzle of caramel sauce over the top. A loose crosshatch pattern gives you caramel in every sip and makes the drink look right, too.