Green Butter (French Vert d’Épinard)

In classical cooking, French sauces may called for "green butter" . In which case you would use the vert d’épinard juice and add it to the butter at a ratio of 1 part juice and 2 parts softened butter. Sauce Velouté Venitienne used such a butter.

Spinach Juice (Vert d'épinard):
4 cups (3½ oz) fresh spinach leaves, washed (100 g)
½ cup water

Green Butter (Beurre vert):
3 Tbsp. vert dépinard (50 g)
6 Tbsp. butter, softened

Spinach Green:
Purée the fresh spinach leaves with a bit of water, until the mixture forms almost a mousse. Then you press it through a chinois to force most of the water out.

Then, you scrape out the solids in the chinois, and put them in a pan, and heat it to 158°F (70°C) Sometimes you have to go a bit higher. The goal though is to heat it until the mixture separates into two - water underneath and coagulate spinach fibre on top - without going so high that the vibrant green colour of the spinach starts to change.

You can make vert d’épinard in advance (in fact, it makes your cooking day less stressful if you do), but it needs to be used up within 1-2 days.

Green Butter:
In a small bowl whip the spinach juice into the butter.

Makes 3 Tbsp. (50 g) of vert d'épinard and 9 Tbsp. green butter.