Preheat Oven: Set your oven to 375°F (190°C).

Prepare the Cream Mixture:

In a large saucepan, combine 2½ cups of light cream, baking soda, 2 teaspoons of kosher salt, and the black pepper.

Add the peeled and chopped potatoes to the saucepan.

Cook the Potatoes:

Bring the mixture to a boil over medium-high heat, stirring occasionally to prevent sticking.

Once boiling, reduce the heat to low and let it simmer gently for 20–25 minutes, or until the potatoes are tender but not falling apart.

Prepare the Topping:

In a separate bowl, mix the panko breadcrumbs, grated Parmesan cheese, 4 tablespoons of melted butter, and the remaining ¼ teaspoon of kosher salt until well combined. Set aside.

Assemble the Casserole:

Once the potatoes are done, remove the saucepan from heat.

Stir in the remaining ½ cup of light cream and 6 tablespoons of butter into the potato mixture until the butter has melted completely.

Transfer the creamy potato mixture into a greased 9x13-inch baking dish, spreading it evenly.

Sprinkle the prepared panko-Parmesan topping evenly over the potatoes.

Bake:

Place the baking dish in the preheated oven and bake for 15–20 minutes, or until the top is golden brown and the casserole is bubbling around the edges.

Serve:

Remove from the oven and let it sit for about 10 minutes before serving to allow the casserole to set.