Squash cooked in its juice, squash vinegar, barley mugi miso
Fall means squash, and this is a dish I served that highlights butternut squash in two different ways. A round slice of squash is cooked in its own juice, and then served with a sauce
made of its own juice and vinegar made from squash. On top is a salty condiment made from walnuts and barley mugi miso, a variety of miso made with barley that is deeply savory and salty.
Like the coffee semifreddo, this is a dish for which I can't take full credit for its components.
The squash vinegar is another technique from the Noma Guide to Fermentation,
and the miso condiment comes by way of Serious Eats.
As always I just hope I've made something greater than the sum of its parts.
The squash vinegar involves adding a high-proof alcohol (vodka for me, since Everclear is unavailable in California) to squash juice, which kickstarts the process of allowing acetic acid bacteria to convert the alcohol to acetic acid. The Noma recipe optionally calls for backslop, aka a dose of a previous batch of vinegar to boost the population of acetic acid bacteria. If you do not have any backslop,
an adjusted quantity of apple cider vinegar is an acceptable substitute and used in this recipe. Finally the mixture is aerated with an aquarium pump attached to a porous air stone. This dramatically accelerates the process to 10-14 days for the alcohol to convert to acid, as opposed to several months. As always, work safely and cleanly and sanitize your equipment.
The vinegar should last indefinitely kept tightly sealed in the refrigerator.
You can use any leftover miso condiment for its originally recommended use as a dip for vegetables, which works quite well, but be careful - a little goes a long way.
For 4 servings.
For the squash vinegar:
1 large butternut squash
Apple cider vinegar or backslop
For the walnut/mugi miso condiment:
30g shelled walnuts, chopped
85g barley mugi miso
50g onion, minced
For the squash:
1 butternut squash
245g squash juice
For the sauce:
Squash juice from cooking, strained
Prepare the squash vinegar (2w in advance):
Peel the squash, cut in half, remove and discard seeds, and cut into pieces. Juice the squash and transfer to a fermentation vessel. The juice will foam substantially during aeration so start with a vessel that is quite large relative to the volume of juice; you can always transfer to a smaller vessel later when foaming has subsided.
Weigh the juice and set at 100%; add 23.4% apple cider vinegar or backslop and 20% vodka. Aerate with an aquarium pump for ~12d or until desired level of fermentation is achieved and the taste of alcohol is no longer present. Strain and transfer to an airtight container; chill until needed.
Prepare the walnut/mugi miso condiment (up to 3d in advance):
Lightly toast the walnuts in dry skillet until aromatic but not browning. Crush in mortar & pestle or food processor. Combine the miso, mirin, sugar, and dashi in a bowl.
Saute the onion in a small pot until translucent. Add the walnuts and miso mixture and cook to a thick paste, ~3m; lower the heat to prevent scorching if necessary. Season with rice vinegar.
Prepare the squash (up to 12h in advance):
Peel the squash. Slice the bulbous end of the squash into rounds about 1/2" thick. Cut the top into pieces and juice. Season the slices with salt and vacuum pack with the juice. Cook sous vide @ 194F for 30m. Strain, reserving the squash and cooking juice separately; strain the juice. Cut the rounds into portions for serving with a ring mold and vacuum pack. Chill the juice and squash rounds until needed.
Reheat the squash for serving in a 134F water bath. Remove, pat dry on paper towels, and sear one side in a very hot pan until browned. Drain on paper towels. To prepare the sauce, reduce the reserved cooking juice heavily, emulsify in butter to desired texture, and season with salt and the squash vinegar. The sauce should be rather acidic, as it cuts the savoriness of the squash and miso. Add a squash round to a serving plate and top with a few spoonfuls of the sauce. Add a small quenelle of the miso condiment on one side of the squash.