To make the syrup, combine water, sugar, and coffee in a small saucepan. Bring to a simmer, stirring occasionally to dissolve sugar. Remove from heat and set aside to cool completely.

To make the filling, whip the cream with the granulated sugar and vanilla in a stand mixer fitted with the whisk attachment until stiff peaks form. Transfer whipped cream to a separate bowl, return bowl to the mixer, and replace whisk attachment with paddle attachment.

To the mixer, add the mascarpone cheese, pumpkin, brown sugar, spices, and salt. Beat on high until combined. Stir in 1/3 of the whipped cream until lightened. Gently fold in the remaining whipped cream until fluffy and combined.

One at a time, quickly dip the ladyfingers in the coffee syrup until soaked but not soggy; arrange in an even layer along the bottom of an 8-inch square dish. (Line the ladyfingers up in two straight rows of six.**) Spread with half of the the mascarpone filling. Repeat with remaining ladyfingers, syrup, and filling.

Cover with plastic wrap and refrigerate for at least 6 hours before serving. Just before serving, place cinnamon in a fine strainer and shake sparingly over the surface. Cut into squares and top with whipped cream, if desired. Tiramisu will stay fresh tightly covered with plastic wrap in the refrigerator for up to 5 days.