In a large pot over medium heat, melt a couple of tablespoons of butter. Add finely diced onions and minced garlic, stirring until the onions are translucent and fragrant, about 4-5 minutes.

Incorporate chopped Yukon Gold or Russet potatoes into the pot. Stirring occasionally, let them cook for about 5-7 minutes until they start to soften.

Pour in enough seafood stock to cover the vegetables and raise the heat to bring the mixture to a gentle simmer. Cook uncovered for 10-12 minutes.

Once the potatoes are tender, lower the heat to medium-low and gracefully pour in the heavy cream along with whole milk. Stir gently for about 2-3 minutes.

Add your white fish, shrimp, scallops, and mussels. Cook gently for another 5-7 minutes or until all the seafood is just cooked through.

Stir in fresh thyme, a bay leaf, and a pinch of salt and pepper to taste. Let the chowder heat through for 2-3 minutes.

Remove the bay leaf before serving, and ladle generous portions of your chowder into warm bowls.