Preheat the oven to 400°F (205°C) and line a baking sheet with parchment paper.
Cook the rice according to the package instructions.
Prepare the fish: Place the fish on the foil-lined baking sheet, season with salt and pepper, and bake for about 10 minutes until the internal temperature reaches 130°F (55°C). Cooking time will vary depending on the thickness of the filet.
Make the lemon sauce: Melt butter in a sauté pan over medium heat. Whisk in the flour and cook for 1–2 minutes. Gradually whisk in lemon juice, chicken broth, and heavy cream. Simmer lightly until thickened. Season with salt and pepper and stir in parsley. Remove from heat.
Let the fish rest for 3–5 minutes while preparing the snow peas.
Cook snow peas: Heat butter in a nonstick pan over medium heat. Add snow peas and sauté until tender but still crisp. Season with salt and pepper.
Make the applesauce: In a saucepan, heat the applesauce until hot.
Make the banana milk: Blend banana, maple syrup, vanilla, milk, water, and ice cubes until smooth. Adjust sweetness or consistency as needed.
Serve: Plate the white fish with lemon cream sauce, rice, sautéed snow peas, warm applesauce, and Korean banana milk.