Heat olive oil in a wide, even-surface pan over medium heat.
Sauté garlic, onion, chili, and thyme until fragrant and onions are translucent.
Add rice and toast briefly for 1-2 minutes, stirring to coat with oil.
Pour in chicken stock and lemon juice, bring to a simmer.
Add prawns and mussels to the pan, nestling them into the rice.
Cook until seafood is done and rice is tender, about 15-20 minutes.
Stir in chopped parsley before serving.
Season with salt and pepper to taste.