Thai Yellow Curry Paste

Yield: about 2 cups

2 medium regular shallots or 6 small red Asian shallots, unpeeled
2 small heads garlic, unpeeled
3- inch 7.5-cm section galangal, peeled and thinly sliced (2 oz / 60 g net)
2- inch 5-cm section ginger, peeled and thinly sliced (1.5 oz / 45 g)
1 generous teaspoon coriander seeds
20 dried red Thai chiles or Mexican chiles de arbol, stemmed
and roughly chopped
5 large stalks lemongrass, trimmed, and cut into thin half-moons (about 6.5 oz / 195 g net)
2 tablespoons ground turmeric
1 tablespoon mild curry powder unsalted preferred
2 tablespoons roughly chopped cilantro stems or roots
2 tablespoons Thai shrimp paste (gapi) or 1 ½ tablespoons fine shrimp sauce (mam tom)
1 ½ tablespoons kosher salt or 2 ¼ teaspoons fine sea salt

Wrap the shallots and garlic in two separate foil packages. Heat a medium or large cast-iron skillet over medium-high heat. Pan roast the shallots and garlic in the skillet for 25 to 30 minutes, turning 3 or 4 times, until soft; poke with a blunt object to test. Set aside to cool for 10 minutes, until easy to handle, then peel and roughly chop; cut the garlic in half and use a knife tip to dislodge the garlic. Set aside.
Arrange the galangal and ginger in a flat layer on a piece of foil, wrap it up into a flat package. Cook until soft over medium-high heat, 5 to 7 minutes, flipping midway; set aside to cool. Meanwhile, toast the coriander seeds in the skillet over medium heat until fragrant and a few pop. Cool, then pound using a mortar and pestle.
While the aromatics roast and toast, soak the chopped chiles in 2 cups hot water for 15 minutes, until soft. Save 2 tablespoons of the liquid before draining the chiles and discarding the remaining liquid. Put the
chiles in the bowl of a food processor. Add the lemongrass, and roasted galangal and ginger. Run the machine to chop, pausing to scrape down the sides.
Add the shallot, garlic, coriander, turmeric, curry, cilantro, shrimp paste, and salt. Run the machine until finely chopped. Add the reserved chile soaking liquid. Run the machine until relatively smooth and paste-like. Transfer to a jar and refrigerate for up to 2 weeks. Or, freeze for several months. Return to room temperature before using.