Preheat oven to 350°F (175°C).

In a large bowl, whisk together the eggs and brown sugar until the mixture is creamy and smooth.

Add the heavy cream, maple syrup, cardamom, and melted butter to the egg and sugar mixture.

Beat all ingredients together until well combined and smooth.

Pour the filling into the prepared pie shell.

Bake in the preheated oven for 55-60 minutes, or until the crust is golden brown and the filling is set but still slightly quivery in the center.

Let the pie cool completely on a wire rack before serving. The filling will continue to set as it cools.

If using a larger pie pan, pre-bake the crust partially by lining it with aluminum foil and weighing it down with pie weights.

Bake the crust at 400°F (200°C) for 10 minutes before adding the filling.