Step 1

(Optional but recommended) Wrap the saffron in a small square of aluminum foil, then toast in a hot pan or oven for about 1 minute. Remove from the pan and set aside to cool.

Step 2

Lightly crush the saffron threads (e.g. with a mortar and pestle) and place into a small container. Pour hot water over the saffron, then loosely cover the liquid and set it aside, ideally for about 4 hours (see note).

Step 3

Lightly crush the cardamom pods with a mortar and pestle in order to break them up into pieces. Place the cardamom in a small saucepan along with the liquid from the saffron (you can filter out the saffron threads now or later), cold water, and the sugar. Heat the mixture on the stove top, stirring frequently to dissolve the sugar. Once the mixture is simmering gently, remove it from heat and let it stand for 30 minutes.

Step 4

Pour the simple syrup through a fine strainer to remove the cardamom and saffron solids. Store in a sealed container in the refrigerator for up to a month.

Step 5

Squeeze enough red grapefruit to yield about 200 ml (a little over 3/4 cup) of juice. Two medium sized grapefruit should do the job. Pour the juice through a fine strainer in order to remove any pith or pulp. Set 15 ml (1 tbsp) aside for the rims, and chill the rest of the juice for the cocktails.

Step 6

Before preparing the drinks, combine the liquids soaking the glass rims in a small flat dish or bowl. In a separate bowl, pour a small quantity of granulated sugar (enough to cover the glass rims - you can always add a little extra if you run low).

Step 7

Prepare 6 champagne flutes by dipping the rims into the soaking liquid, then into the granulated sugar. Set them aside.

Step 8

To each cocktail, add 15 ml (1/2 oz) of simple syrup and 30 ml (1 oz) grapefruit juice. Top up each glass with about 125 ml (1/2 cup or 4.2 oz) of chilled sparkling Cava. Garnish with grapefruit zest and serve immediately.