Preheat oven to 350°F.
In a large bowl, beat together pumpkin puree, eggs, half and half, brown sugar, pumpkin pie spice, and salt until smooth.
Pour the mixture into 3 greased 10-ounce cups.
Place cups in a 9×13 baking pan; pour hot water around cups to a depth of 1 inch.
Bake at 350°F for 20 minutes.
Meanwhile, in a separate bowl, combine brown sugar, pecans, and butter.
After custard has baked for 20 minutes, sprinkle topping over the custard and bake for an additional 35-40 minutes, or until a knife inserted in the center comes out clean.
Serve warm or chilled; top with whipped cream, cinnamon, and more chopped pecans if desired.
Store in the refrigerator.