2 tablespoons unsalted butter
1 cup granulated sugar
1 15-ounce can sweet potatoes
8 large eggs, separated, at room temperature
1 cup heavy cream at room temperature
2 teaspoons ground cinnamon
1 1/4 cups pure maple syrup
Preheat oven to 350 degrees F. Butter eight 4-inch, 1-1/4 cup-capacity individual souffle dishes. Dust bottoms and sides lightly using 2 tablespoons sugar and set aside.
In a large bowl, mix together sweet potatoes, egg yolks (reserve whites), cream, 3/4 cup sugar, cinnamon, and 1/4 cup maple syrup; beat until smooth. Set aside.
In a separate bowl, beat egg whites with remaining 2 tablespoons sugar until soft peaks form. Add one-quarter of the egg whites to the bowl with sweet potato mixture and gently fold in with a rubber spatula. Fold in the remaining egg whites until just incorporated.
Arrange prepared souffle dishes evenly spaced on a flat baking sheet. Fill each dish no more than two-thirds of the way up with sweet potato mixture and bake for 20 to 25 minutes.
Meanwhile, in a small saucepan, heat remaining 1 cup maple syrup over low heat.
Serve souffles immediately with warm maple syrup.