Preheat oven to 375° and place sliced ginger in an aluminum foil packet with a dab of olive oil. Seal the packet shut and place in oven for 15-20 minutes or until ginger is fragrant. Roasting the ginger will intensify the flavour and make for a more flavourful broth.
Parboiling means to partially cook something (by boiling) before using the preferred method to cook your food. In this case, we’re parboiling the chicken drumsticks to remove the impurities for a clear broth. When chicken is boiled, foamy white gunk floats to the surface. This won’t kill you, it’s just coagulated protein. But to get rid of that, fill your pot with enough water to cover the chicken and vigorously boil for 5 minutes. Strain the chicken in a colander and wash off all the gunky bits. Return chicken to pot and fill with 3 quarts chicken broth.
Simmer ingredients for 1½ hrs. to infuse.
Simmer broth and slowly get to a rolling boil. Add lemongrass, whole cloves, whole star anise, roasted ginger, cardamom pods, yellow onion, and cilantro to pot. After boiling for a minute or two, bring heat back down to low and simmer covered for 1½ hours.
Remove chicken, strain broth.
After 1½ hours, remove the chicken drumsticks from the broth. The meat will be really tender, so it should be easy to debone the chicken. Set aside the meat pieces. After the chicken is removed, strain the broth in a mesh sieve and discard the solids. Return the strained broth back to the pot and bring back to a simmer. Add sugar, fish sauce, and salt to taste. Here’s where you can taste and adjust to balance out the sugar, fish sauce, and salt to your preference. If the broth has reduced too much, you can add 1-1½ cups of water to the broth. Be careful when doing so – it will water down the flavour, so continue tasting as you go.
In a separate pot, prepare the vermicelli noodles by filling with water and bringing to a boil. Add dry noodles in and boil for 5 minutes, or as instructed by package (different brands may vary in cooking time). Cook until soft and strain in colander. Transfer to serving bowl and ladle hot broth over the noodles, then garnish with chicken meat, cilantro, and sliced onion (or garnish as desired). Congrats! You just made phở gà.