Position an oven rack in the lower third of the oven and heat the oven to 375°F.
Make the filling
Put the pumpkin purée, maple syrup, cinnamon, nutmeg, ginger, cloves, and salt in a medium bowl or 4-cup measure (this makes it easy to fill the tarts). Whisk until well blended and smooth. Add the egg and vanilla and whisk until just blended.
Line the tart pans
Lightly grease ten regular-sized (2-3/4-inch diameter) muffin cups. If using homemade dough, roll it out to a 1/8-inch thickness on a very lightly floured surface. If using store-bought dough, unroll it on a very lightly floured surface. Using a 3-1/2-inch round cookie cutter, cut out 8 rounds. Gather up the scraps, reroll to a 1/8-inch thickness, and cut another round. Reroll and cut one more round for a total of 10 rounds of dough.
Working with one round at a time, use your finger to gently press the dough into a prepared muffin cup, making sure that there are no air bubbles in the bottom and that the dough is pressed firmly and evenly up the side to within 1/4-inch of the top of the cup. Repeat with the remaining dough rounds.
Fill and bake the tarts:
Evenly spoon (or pour if you’re using a 4-cup measure) the filling into the lined muffin cups. Bake until the crusts are golden brown and the centers jiggle slightly when the pan is nudged, 27 to 29 minutes.
While the tarts are baking, make the streusel topping. Put the pecans, brown sugar, and cinnamon in a food processor and pulse until the nuts are finely ground.
Move the muffin tin to a wire rack and let cool for 10 minutes. Using a thin, metal spatula or the tip of a paring knife, carefully remove the tarts from the muffin cups and set them on a wire rack. Serve warm or at room temperature. Just before serving, sprinkle the tops with some of the pecan streusel.
Make Ahead Tips
The tarts can be filled, covered in plastic, and stowed in the refrigerator for up to 1 day before baking.
Photo: Sarah Breckenridge