Preparation Steps

• Brew a concentrated batch of coffee: make 1 1/2 cups (12 fl oz) using your preferred method, using roughly twice the usual coffee grounds so the flavor stays bold after ice is added. Aim for a 5-minute brew time for drip or press methods.
• While the coffee brews, stir together the simple syrup and vanilla in a small bowl so the vanilla can bloom; if you don’t have simple syrup ready, dissolve 2 tbsp sugar in 2 tbsp hot water and cool briefly.
• Fill two tall glasses with the ice. As soon as the coffee is ready, pour it over the ice to rapidly chill and slightly dilute the concentrate — this prevents a cloudy drink and cools the coffee fast.
• Divide the milk between the glasses, then add half of the simple syrup–vanilla mix to each. For a creamier texture, use whole milk or substitute half-and-half for up to half the milk amount.
• Stir each glass vigorously with a long spoon, or transfer the contents to a tight-lidded jar and shake for 10–15 seconds to emulsify and create a light foam on top.
• Taste and adjust sweetness by adding a little more simple syrup if needed. Finish with a tiny pinch of ground cinnamon over the foam, then serve immediately.