Heat the coconut oil in a large pot or Dutch oven on medium heat.
Add the red curry paste, garlic and chiles and fry for about 5 minutes.
Pour in the chicken stock, fish sauce and coconut milk and bring to a simmer.
Carefully drop in the chunks of butternut squash, bring back to a simmer and cook for approx. 5-10 minutes.
Add the sliced chicken and continue cooking another 5-10 minutes.
When the chicken is close to being done, add the sliced mushrooms, simmering until the chicken is cooked thoroughly and mushrooms are soft – about 5 more minutes.
Combine the cashews with the curry and allow them to be heated through.
Just before serving add the avocado and fresh cilantro.