Preheat and prep. Heat the oven to 375°F (190°C). Place a rack in the lower third of the oven for even bottom crust browning.

Blind-bake the crust. Line the pie shell with parchment and fill with pie weights or dried beans. Bake for 15 minutes. Remove the weights and parchment, prick the bottom lightly with a fork, and bake 5–8 minutes more until the edges are lightly golden. Reduce oven temperature to 325°F (165°C).

Warm the dairy. In a small saucepan, combine the heavy cream and milk. Warm over low heat until just steaming, not boiling. Take off the heat and let it cool for 5 minutes.

Mix the custard base. In a large bowl, whisk the eggs, maple syrup, brown sugar, vanilla, cinnamon, nutmeg, and salt until smooth and well combined.

Temper the eggs. Slowly pour the warm dairy into the egg mixture while whisking steadily. This prevents scrambling and keeps the custard silky.

Add butter. Whisk in the melted, slightly cooled butter for extra richness and a glossy finish.

Strain for smoothness (optional but recommended). Pour the custard through a fine-mesh sieve into a large measuring cup or bowl. This removes any bits and guarantees a smooth texture.

Fill the crust. Place the par-baked crust on a rimmed baking sheet. Carefully pour in the custard. Lightly grate a pinch of nutmeg over the top, if you like.

Bake low and slow. Bake at 325°F for 35–45 minutes. The edges should be set, and the center should still wobble slightly when you nudge the pan. Do not overbake.

Cool completely. Transfer to a rack and let cool to room temperature, about 2–3 hours. The custard will finish setting as it cools.

Chill and serve. For the cleanest slices, chill at least 2 hours. Serve plain or with lightly sweetened whipped cream and a dusting of nutmeg.