Fill a highball glass with ice cubes.
Pour 45ml of tequila blanco over the ice.
Add 90ml of fresh orange juice and stir briefly to combine with the tequila.
Slowly pour 15ml of grenadine syrup down the inside edge of the glass or over the back of a bar spoon so it sinks to the bottom, creating the sunrise gradient effect - do not stir after adding grenadine.
Garnish with a half orange slice on the rim and serve immediately.
The sunrise effect only works if the grenadine is added last and undisturbed - its higher sugar density causes it to sink naturally through the juice. Using freshly squeezed orange juice rather than carton juice dramatically improves both flavor and the clarity of the gradient.
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