Heat oven to 325°F. Prepare a large roasting pan (or two) that will fit 6-8 ramekins. Caramelize the pumpkin puree in a shallow saucepan over medium-heat for about 10 minutes, stirring regularly. In a large bowl, whisk the egg yolks with the white and brown sugars and set aside
Once caramelized (but not burnt!), whisk the cream, milk, and vanilla into the pumpkin puree and bring the mixture to a simmer. Remove from heat and add the salt and all the spices.
Add ¼ cup of the pumpkin-cream mixture to the egg-sugar mixture and whisk to temper the eggs. Slowly whisk in the rest of the pumpkin-cream mixture while pouring it into the bowl in a thin stream. Add the maple syrup and the bourbon.
Divide the mixture among your ramekins and place them in the roasting pan(s). Fill the pan(s) with hot water half-way up the sides of the ramekins. Carefully place in the oven – the water may slosh as you move it so mind it doesn’t end up in the custards. Bake for 40-60 minutes until set.
Remove the custards from the pan and place on a cooling rack. For food safety reasons, you don’t want to leave the custards un-refrigerated for long, so allow them to sit just until they are cool enough to handle, 15-20 minutes. Transfer to a tray or pan, cover with saran wrap, and chill in the fridge, 2 hours to overnight.
Right before serving, sprinkle a tablespoon or so of raw sugar on each chilled ramekin of pumpkin custard and caramelize the tops with a brulée torch (be sure to follow all instructions related to this piece of equipment). If you try to do this step earlier and then refrigerate, the caramelized sugar will loosen and start to get watery. They still taste fine, but its definitely not as pretty, so it's best to wait. Enjoy!