Wash the oranges well if using fresh slices. Slice the banana into smaller pieces for easier blending. Measure all ingredients before starting. This helps the recipe come together quickly and keeps the texture smooth.

Pour orange juice, milk, vanilla extract, heavy cream, and sugar into the Ninja slushie machine. Add banana pieces and frozen orange slices next. The creamy ingredients help create the famous smooth Orange Julius texture.

Add ice cubes carefully into the machine. Blend until the mixture becomes thick, creamy, and frosty. The texture should feel smooth without large ice chunks remaining in the drink.

Taste the slushie before serving. Add extra sugar if you want more sweetness. You can also add extra orange juice for stronger citrus flavor. Blend again for a few seconds after adjustments.

Pour the creamy slushie into tall serving glasses immediately. The drink tastes best while very cold and frosty. Garnish with orange zest or a fresh orange slice for extra color and flavor.

Serve the slushie right away with straws or spoons. The creamy orange flavor tastes refreshing and sweet. Enjoy it during warm afternoons, parties, or relaxing weekends with family and friends.