Seaweed and Mushroom Umami Gravy

This is the most deliberately savoury gravy on the site. Kombu seaweed and dried shiitake mushrooms are the two great vegetarian sources of savoury flavour, and used together they multiply each other rather than just adding up. Steep them, do not boil them, and you get a gravy with astonishing depth for something with no meat anywhere near it.

Ingredients

Makes about 550ml, five servings

• 10g (1/3oz) dried kombu seaweed one large piece
• 20g (3/4oz) dried shiitake mushrooms
• 700ml (1 1/4 pints) cold water
• 2 tbsp vegetable oil
• 1 onion, finely chopped
• 2 cloves garlic, crushed
• 1 tsp grated fresh ginger
• 2 tbsp tamari
• 1 tbsp mirin or 1 tsp sugar with 1 tsp rice vinegar
• 2 tbsp cornflour mixed with 4 tbsp cold water
• 1 tsp toasted sesame oil optional, to finish

Kit

• Saucepan
• Fine sieve
• Small bowl

Method

1. Put the kombu and shiitake into the cold water and leave them for at least 30 minutes, or overnight in the fridge if you are organised. Cold steeping draws out the savoury compounds without the bitterness heat brings.

2. Put the pan over a low heat and bring it slowly up to just below a simmer, which takes about 10 minutes. Take the kombu out the moment small bubbles appear at the edges. Boiled kombu turns slimy and bitter.

3. Let the shiitake carry on at a bare simmer for 10 minutes, then lift them out. Squeeze them over the pan, slice them thinly and set them aside. Strain the broth through a fine sieve.

4. Heat the oil in a clean pan and cook the onion over a medium heat for eight minutes until soft and golden, then add the garlic and ginger for one minute more.

5. Add the sliced shiitake and fry for three minutes so they take on a little colour. Rehydrated shiitake are meaty and will brown nicely.

6. Pour in the strained broth, add the tamari and mirin and simmer for six minutes so it reduces slightly and pulls together.

7. Whisk in the cornflour slurry and cook for two minutes until thickened and glossy. Finish with the sesame oil if using, taste and season. It should be deeply savoury with a faint marine sweetness.

Tips worth knowing

• Never boil kombu. The moment it simmers it starts releasing bitter compounds and a slippery texture that ruins the broth.
• The white dusty film on dried kombu is not mould, it is salt and savoury minerals. Wipe it lightly at most, do not wash it off.
• Steeped kombu and shiitake can be sliced and eaten. Do not bin them, they are good chopped into a stir fry.
• As written this is gluten free thanks to the tamari and cornflour, but check the mirin, since some cheaper versions contain added ingredients.

Keeping and reheating

Four days in the fridge and two months in the freezer. The broth itself, before thickening, freezes perfectly and is worth making in double quantity.

Questions people ask