Prepare the chicken by shredding cooked chicken breast. I poached 2 chicken breasts in chicken stock, then shredded. You can certainly use shredded rotisserie chicken instead, if you'd like.
Take the piece of lemongrass and hit it a few times with the back of your knife. This will release the flavor into the soup, which really adds so much!
Heat a large pot to medium, add in the butter and oil and sauté the mushrooms and red pepper for a few minutes. Add in the ginger and garlic, sauté for about 20 seconds, then stir in the curry paste and allow to toast for 10 seconds.
Deglaze the pan with the chicken stock (I used the remaining poaching stock, along with more chicken stock). Add in the coconut milk, chicken, lime juice/zest, fish sauce, lemongrass and scallions.
Simmer for 15 minutes, uncovered. Add in the zucchini and allow to cook 5 more minutes or until tender. Discard the lemongrass, garnish with fresh cilantro and swerve with a squeeze of lime! Store leftovers in the fridge for a few days or freeze.
If you don't like too much spice, you can reduce the red curry down to just 1 tablespoon. The soup will still have tremendous flavor, but will be a bit milder.