Mix together all ingredients in a 1 liter pitcher or carafe.
Serve in champagne or martini cocktail glasses.
This cocktail isn't typically served with ice, so it's best to use oranges that have been previously refrigerated for your orange juice, and use cava that has been chilled.You can also make it several hours ahead of time and chill it in the refrigerator until it is ready to be served. That also allows the flavors to meld together properly. Mix the cocktail again before serving it. Alternate recipes:
For a bit stronger version, you can try 2 parts orange juice, 2 parts cava, 1 part vodka, and 1 part gin.
I have since found a Facebook page with what is claimed to be the original recipe. It includes 1 full bottle of cava, 1 generous glass of orange juice, a shot of gin and a shot of vodka.