Place the red onions in a medium bowl. Combine 1 cup of the vinegar, 1 cup water, 1 cup salt, and the sugar, allspice, cinnamon and star anise in a small saucepan. Bring to a boil, then lower to simmer and cook until slightly reduced, about 10 minutes. Pour the liquid and spices over the onions. Let cool, then cover with plastic wrap and refrigerate for at least 1 day.
Place the macadamia nuts in a small skillet over medium-high heat and cook, tossing, until golden brown and fragrant, about 3 minutes. Transfer the nuts to a bowl and season with salt and white pepper. Let the nuts cool completely, then roughly chop.
Heat the canola oil in a large skillet over medium heat. Add the garlic, yellow onions and ginger, and cook, stirring occasionally, until soft and lightly caramelized, about 10 minutes. Carefully pour in the brandy and tilt the skillet slightly so the alcohol catches flame. Once the flame dies down, scrape the bottom of the skillet to loosen any caramelized bits and then continue cooking until the brandy is reduced by half, about 1 minute. Add the liver pate and cook, stirring, until fully heated through, about 5 minutes.
Scrape the liver mixture into a food processor and blend until smooth. Press the mixture through a fine-mesh strainer into a bowl, discarding any solids. Add the remaining 1/4 cup vinegar, the sriracha, mirin, soy sauce, fish sauce, sesame oil, lime juice and all but 1 teaspoon lime zest and whisk to combine.
Add the rice noodles to the liver sauce, toss until evenly coated, and then transfer the noodles to a serving platter. Drain the pickled red onions from their liquid and sprinkle evenly over the noodles. Top with the macadamia nuts, cilantro, scallions and the reserved lime zest.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Use extreme caution when igniting alcohol. Remove the pan from the heat source before adding the alcohol. Pour the alcohol into the pan and carefully ignite with a match or click lighter. Return the pan to the heat and gently swirl to reduce the flames.