Bánh Mì-Inspired Rillettes

• 10½ cups (2½ liters) water
• 2 bunches cilantro, divided

In a large pot, pour in the water and add 1½ bunches of the cilantro, 4 teaspoons of the salt and 3 pinches of the pepper. Chop the onion and 1½ of the carrots into large cubes and add them to the pot. Bring to a boil; reduce heat to a simmer and cook for 30 minutes. While vegetables simmer, halve the zucchinis lengthwise, sprinkle with the remaining 1 pinch each of salt and pepper, and drizzle