Burnt Onion Steak Sauce

INGREDIENTS

Grapefruit, large red

3-inch piece Lemon, zest

3-inch piece Orange, zest

1 1/4 cups

Raisins

1/2

Yellow onion, large whole

2 cups

Beef stock

3/4 cup

Tomato paste

3 tbsp

Balsamic vinegar

3 tbsp

Barley malt syrup

3 tbsp

Caper, juice

1/4 cup

Capers

1 tbsp

Soy sauce

7 tbsp

Worcestershire sauce

2 tsp

Celery seeds, toasted

3 1/2 tbsp

Gochujang

3/4 cup

Champagne vinegar

1 1/2 sticks

Butter, unsalted

1 tablespoon colatura (Italian anchovy sauce)