Thick, chewy maple pumpkin snickerdoodles made with nutty brown butter and rolled in maple cinnamon sugar. The maple syrup and pumpkin are cooked down together in the pan, which drives off the excess moisture and concentrates both flavors at once.
Use dark maple syrup, sold as Grade A Dark Robust. Golden and amber grades are too delicate to survive baking. Do not substitute pancake syrup, which is corn syrup and flavoring and will taste flat.
If you cannot find maple sugar, use the same amount of granulated sugar in the coating. The maple extract in the dough will carry the flavor instead.
Use plain canned pumpkin puree rather than pumpkin pie filling, which is already sweetened and spiced.
The reduction time varies a great deal with pan width, so rely on the spoon trail rather than the clock. Once the water has cooked off, the pan heats quickly and the maple sugars will catch, so pull it off the heat as soon as the trail holds.
Only the yolks are used because whole eggs bring extra water into a dough that already carries moisture from the pumpkin and syrup.
Cream of tartar provides the tang and soft crumb of a true snickerdoodle. If you have none, replace it and the baking soda with 2 1/4 tsp baking powder, though the flavor will be milder.
If the cookies bake up puffy and cakey, the mixture needed longer in the pan. If they spread thin, the dough was too warm and needs a longer chill.
Store cooled cookies in an airtight container at room temperature for up to 3 days, with parchment between layers to protect the coating. A slice of sandwich bread in the container keeps them soft.
Baked cookies freeze for up to 2 months. Portioned dough balls also freeze well before coating. Thaw in the refrigerator overnight, let them sit at room temperature for 15 minutes, then roll in the maple sugar and bake as directed.