Preheat oven to 350℉ (180℃).

Line two baking sheets with parchment paper or silicone baking mats.

Combine gluten-free flour, salt, ginger, cinnamon, baking powder, and baking soda in a bowl. Set aside.

In a large bowl, add the vegetable oil, pumpkin purée, eggs, and brown sugar. Whisk together until smooth and well combined.

Add the flour mixture to the pumpkin mixture and stir with a spatula until fully combined and no streaks of flour remain.

Scoop about 1 ½ tablespoons of cookie dough for each cookie and place them on the prepared baking sheets, leaving about 1 ½ inches of space between each.

Bake for 12 - 15 minutes in the preheated oven. Cookies are done when a toothpick inserted in the center comes out clean.

Let cookies cool for 10 minutes, then transfer to a wire rack to cool completely.

Using a hand mixer or stand mixer, beat the cream cheese and butter together until smooth and no lumps remain, about 2 minutes.

Add the powdered sugar and cinnamon to the bowl. Start mixing on low speed, then increase to medium. Mix until the filling is smooth and creamy.

Spread about 1 ½ tablespoons of filling onto the flat side of half the cookies, then place another cookie on top and gently press to seal the whoopie pie.