Line a rimmed baking sheet with triple layer of paper towels. Spread pumpkin purée over towels. Press with second triple layer of paper towels until towels are saturated.

Peel off top layer of towels and replace with another layer, flip towels over and peel off saturated towels, being sure to scrape any pumpkin off towels. Continue blotting dry until pumpkin measures ¼ cup or 60 grams (it should be very dry and almost doughy in texture).

Add cream cheese to a stand mixer fitted with paddle attachment; beat until smooth. Add sugar and beat to combine. Add drained pumpkin and beat to combine. Add egg and beat to combine; scraping down sides of bowl as needed. Add cornstarch, pumpkin pie spice, cream of tartar and salt and beat to combine. Cover with plastic and refrigerate for up to 2 days.

Heat oven to 400ºF (204ºC) with rack set in lower-middle position. Line two baking sheets with parchment paper.

Unroll pie crusts on parchment paper or a lightly floured counter. Using a 2 ½-inch round cookie cutter, cut out 11 rounds from each pie crust; transfer to baking sheet, spacing 1 inch apart. Prick each round three times with a fork.

Bake until puffed and dry to touch and lightly golden on bottoms, 8–10 minutes. Remove from oven and immediately flip pie crust pieces over; cool completely (can be stored in zipper-lock bags at room temperature for up to 2 days).

In a medium bowl, combine dry ingredients. Using your fingers, work butter into dry ingredients by pinching and smearing with flour, until a crumbly yet uniform mixture comes together.

Spoon 1 leveled tablespoon of pumpkin filling onto center of each pie crust round, spreading to nearly reach edges.

Holding crust round over bowl of streusel, pick up a handful of streusel and sprinkle it over filling; it needs to be nearly completely coated so shower it with streusel.

Set on prepared baking sheet and repeat with remaining pie crusts, filling and streusel.

Bake until filling is puffed and streusel it starting to brown around edges, about 11 minutes.

Remove and cool slightly on pans before transferring to a wire rack to cool completely.