Boil three sweet potatoes, with their peeling on, in a covered pot over medium heat, until the sweet potatoes are very soft and tender. Test with a sharp knife. If there is any resistance, boil until a knife penetrates the potatoes smoothly. Remove potatoes from the water and let them cool. When they’re cool enough to handle, peel potatoes, cut into chunks and place in a large bowl or food processor. Mash potatoes thoroughly until completely smooth.

Measure two cups of the sweet potato mash and place it into a medium sized pan with the packed brown sugar, all of the spices, salt, the 1/2 stick butter, and one 5 oz can of evaporated milk. Cook on low for about 5 minutes, whipping with a wire whisk until butter and brown sugar are completely melted, and the mixture is blended, smooth and just beginning to bubble. Remove from heat and let cool in the pan.

In a medium sized bowl, beat the three eggs with a fork. Add the second 5oz can of evaporated milk, granulated sugar and vanilla to the eggs, and continue beating until creamy. Pour the cooled sweet potato mixture into the egg mixture. Blend thoroughly with a whisk and refrigerate mixture overnight or use immediately.

Pour into a 9-inch prepared crust.

Place a cookie sheet into the oven. Preheat oven to 450 degrees F. Place pie directly onto preheated cookie sheet, and bake for 10 minutes to set the crust, and to keep it from getting soggy. Turn the oven down to 325 degrees F. and bake for another hour. The crust should be brown and the sweet potato mixture will be puffed up, but still slightly wiggly in the center. After 1 hour, remove pie and place onto a wire rack to cool. The pie will firm up more as it cools.

Serve room temperature with whipped cream.