Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a medium bowl, whisk together the flour, cream of tartar, baking soda, baking powder, salt, cinnamon, and nutmeg. Set aside.

In a large mixing bowl, beat the butter, vegetable oil, and pumpkin puree together until smooth and creamy.

Add the granulated sugar and brown sugar to the butter mixture and beat until well combined.

Mix in the egg yolk and vanilla extract, blending until fully incorporated.

Gradually add the dry ingredients to the wet ingredients, mixing just until combined. The dough will be soft and slightly sticky.

In a small bowl, combine the 1/4 cup granulated sugar and 1 teaspoon ground cinnamon for rolling.

Scoop out 1 1/2 to 2 tablespoons of dough and roll it into a ball. Gently roll the dough ball in the cinnamon-sugar mixture to coat.

Place the coated dough balls onto the prepared baking sheets, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are set and the centers look slightly underbaked. Do not overbake.

Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

While the cookies cool, prepare the maple glaze. In a small bowl, whisk together the powdered sugar, maple syrup, vanilla extract, and pinch of salt. Add milk, 1 teaspoon at a time, until the glaze reaches a pourable consistency.

Drizzle the maple glaze over the cooled cookies and let it set for about 15 minutes before serving.