In a large bowl, combine ground chicken, panko, egg, parmesan, half the minced garlic, salt, and pepper.
Form the mixture into approximately 16 evenly sized meatballs.
Heat olive oil in a large skillet over medium-high heat and sear meatballs until browned on all sides, about 8-10 minutes, then remove from pan.
In the same skillet, melt butter and add sliced mushrooms, cooking until browned and moisture has evaporated.
Add remaining garlic and thyme, sautéing for 1 minute until fragrant.
Whisk in chicken broth and heavy cream, scraping the bottom of the pan to release browned bits.
Bring the sauce to a gentle simmer and return the meatballs to the skillet.
Cook for 5-7 minutes until the sauce has thickened and meatballs are cooked through to an internal temperature of 165 degrees Fahrenheit.
Garnish with fresh parsley before serving.