Place shiitake mushrooms in a bowl and pour boiling water. Place another bowl on top to keep the mushrooms submerged and let sit for 30 minutes. Squeeze excess water and cut mushrooms into thick slices. Reserve ¼ cup mushroom water, straining any sediment.

Combine mushroom water with 2 tablespoons oil, brown sugar, fish sauce, lemongrass, garlic, shallots, ginger, salt, and pepper in a blender. Puree until smooth. Pour marinade over chicken, turning to coat. Marinate for at least 2 hours or overnight.

Wash jasmine rice until the water turns clear. Soak jasmine rice with water and let sit for 25 minutes. Strain and set aside.

Heat remaining tablespoon of oil in a large pot or Dutch oven over medium heat. Remove chicken and mushrooms from marinade and lay in the pot. Sear the chicken until golden brown, flip and sear on the other side. Add coconut water and bring to a simmer. Cover the pot, reduce heat to low, and continue to simmer for 20 minutes.

Remove the lid and skim as much as the fat on top as you can. Add rice, gently shaking the pot to redistribute the rice. Try to keep all of the rice grains in the liquid and not sitting on top of the chicken. Cover the pot and continue to cook on low for another 15-20 minutes or until the rice is tender. Remove from heat and let sit for 10 minutes.

Remove the lid and gently fluff up the rice with a fork. Sprinkle chopped scallions and crispy shallots on top and serve immediately.