Add the heavy whipping cream, milk, sugar, and optional salt into a small jar or cup. If you want flavored cold foam, add your chosen flavoring at this stage. Stir lightly so everything begins to blend together.
Place the handheld frother into the mixture and begin frothing on medium speed. Move the frother around the container to ensure all ingredients are incorporated evenly. This helps create a consistent texture throughout.
Continue frothing until the mixture becomes light, creamy, and slightly thickened. Be careful not to over-froth because it can quickly become whipped cream. The ideal consistency should remain smooth and pourable.
Pour the finished cold foam over iced coffee, cold brew, or even hot coffee. The foam should float beautifully on top while slowly blending into the drink. Serve immediately for the best texture and flavor.
Cold foam tastes best when made right before serving. Its airy texture is freshest immediately after frothing. Enjoy it while it is light, fluffy, and perfectly creamy.