In a mixing bowl, whisk together heavy cream, whole milk, and sweetened condensed milk until smooth.

Stir in vanilla extract and salt, whisking for 30 seconds to incorporate.

Gently fold in any optional mix-ins, being careful not to over-stir.

Pour the mixture into Creami cups, filling to one inch below the rim.

Tap the cups gently on the counter to remove air bubbles.

Place cups upright in the freezer and freeze for at least 4 hours until solid.

Once frozen, install the Ninja Creami machine on a level surface and allow it to acclimate at room temperature.

Insert a frozen cup into the machine and select your desired texture (e.g., gelato or sorbet) and process for 30–60 seconds.

Serve immediately in chilled bowls to maintain the soft-serve texture.