If using homemade pumpkin puree, blend it a little more before using to make it an extra fine puree.
In a medium bowl, whisk together 3 whole eggs and ½ cup sugar until well blended.
Heat 1¾ cup heavy whipping cream in a sauce pan, almost to a simmer; stirring frequently to prevent scorching.
Slowly add hot cream while whisking (Adding it to quickly can result in scrambled eggs = not good!)
Strain the cream/egg/sugar mixture through a strainer into a large measuring cup or bowl with a pouring lip.
Whisk in 1 cup pumpkin puree and ¼ tsp cinnamon.
Divide the mixture into 8 (4 oz) cups and place in a large casserole baking dish or into 2 dishes if they don't fit.
Fill the baking dish with boiling water about halfway up the sides of the ramekins. Bake at 300˚ F for 35-40 minutes. The creme brulee centers should barely wiggle when you move the pan.
Cool to room temperature then cover and refrigerate until ready to serve. Note: don't caramelize until ready to serve.
Making the Crisp topping:
Brulees must be at room temp or cold to caramelize the tops. Don't refrigerate after caramelizing, or the sugar will melt. Put 1 to 2 teaspoons of sugar on each custard, swirl to spread evenly. Torch the tops moving in a circular pattern until the whole surface is caramelized and sugar turns a rich amber color. When you're ready to eat it, break the sugar topping with a spoon to break it up.