Prepare your pie crust, if you're making a homemade pie crust. Then, make the brown butter by cutting the butter in small pieces and heating the butter in a small pan on medium heat for about 3-5 minutes until the butter turns an amber color. The butter will first foam and start to pop. Then, brown bits will begin to form in the bottom of the pan. Once browned and popping slows, it is ready. You should smell a nutty aroma. Scrap the butter (and all the of those magical brown bits into a heat-safe bowl and let rest for about 10-15 minutes, until cooled.
Then, preheat the oven to 350 degrees. While the oven is preheating, add the pumpkin puree, sugar, brown butter, vanilla extract, eggs, egg yolk, heavy cream, spices, corn starch, and salt to a mixing bowl. Whisk everything together until well combined.
Pour the pumpkin pie filling into the pre-baked crust.
Then, bake the pie at 350 degrees for 50-60 minutes until the pie is set. A slight jiggle is ok (the pie may be a little puffed). Then, remove the pie from the oven and let it cool on a wire rack until set and completely cooled. Top with whip cream and cinnamon, then, serve and enjoy!