Combine the base: In a medium saucepan, whisk together sweetened condensed milk, whole milk, and heavy cream. If you prefer a lighter creamer, use more milk and skip the cream.
Warm gently: Set over low to medium-low heat.
Warm until steam rises and tiny bubbles form at the edges, 4–6 minutes. Do not let it boil.
Add the vanilla: Remove from heat. Stir in vanilla extract and, if using, vanilla bean paste.
Add a pinch of salt to sharpen the flavor.
Taste and adjust: Want it sweeter? Add 1–2 tablespoons of sugar or maple syrup. Want it richer?
Splash in a bit more cream.
Cool and store: Let cool to room temperature. Pour into a clean glass bottle or jar with a tight lid. Refrigerate until chilled.
Use and enjoy: Shake well before each use.
Start with 1–2 tablespoons per cup of coffee, then adjust to taste.