Preheat the oven to 375°F (190°C).

Peel and slice the root vegetables into thin pieces, about 1/8 inch thick. Chop the onion and garlic.

Sauté the onion and garlic in olive oil over medium heat until translucent and fragrant, about 4-5 minutes.

In a mixing bowl, combine the heavy cream and shredded cheese until melted together.

Layer the sliced vegetables in a greased baking dish, alternating between potatoes, carrots, and parsnips. Season with salt and pepper between layers.

Pour the cheese and cream mixture evenly over the layered vegetables.

Sprinkle panko breadcrumbs and fresh herbs on top for garnish.

Bake in the preheated oven for 40-50 minutes until golden brown and bubbly.

Let rest for 10 minutes before serving.