Pour the heavy cream into a standard ice cube tray the night before. Freeze it at least 8 hours, until each cube feels solid with no soft center. Half-frozen cubes are the fastest way to end up with a thin, soupy mixture.

Add the frozen cream cubes, chilled milk, sugar, and salt to the Vitamix container first. Save the vanilla for later; blending it in too early mellows its scent under the motor’s heat. Twist the lid on tight and set the tamper into its port.

Run the blender on its lowest speed for about 6 seconds to break the cubes into smaller pieces. You’ll hear a rough, clattering sound as they bounce around. That settling into a steady hum means it’s time to increase speed.

Move the dial to medium-high, then push the tamper down through the center port in short, steady strokes to guide the cubes into the blades. The motor may bog down and sound strained; keep tamping steadily instead of pausing, since stopping lets the cubes re-freeze against the sides.

Once the mixture stops clattering and starts to mound around the tamper, add the vanilla and blend another 10 to 15 seconds. The finished texture should look like soft serve, thick enough to hold a swirl when the tamper lifts out.

Overblending past this point melts it back into something closer to a milkshake, and the only fix is refreezing the batch into cubes and starting over.

Scoop straight from the blender for a soft-serve texture, or move it to a freezer-safe container for 40 minutes to 2 hours for something closer to scoopable ice cream.

Press parchment onto the surface before sealing the lid to cut down on ice crystals.