Make vanilla syrup first: Combine water and sugar in a small saucepan over medium heat. Stir until sugar dissolves completely, about 3 minutes. Remove from heat, stir in vanilla bean paste, and let cool to room temperature. Store in refrigerator.
Brew 2 shots of espresso or 1/4 cup strong coffee using your preferred method. Pour into a preheated 12-ounce mug.
Add 2 tablespoons of vanilla syrup to the hot espresso and stir to combine. Taste and adjust sweetness if needed.
Heat milk in a small saucepan to 150-160°F, or use a milk frother or steam wand. If using a saucepan, whisk vigorously or use a handheld frother to create foam.
Tap the milk container on the counter to eliminate large bubbles, then swirl gently to create a smooth, velvety texture.
Pour steamed milk into the mug with espresso, holding back foam with a spoon. Once the mug is nearly full, spoon remaining foam on top.
Dust with a pinch of vanilla bean paste or cinnamon if desired. Serve immediately while hot.