Heat the oven to 425°F. Line a 13×18-inch rimmed baking sheet with parchment paper; coat the parchment and sides of the pan with nonstick cooking spray.
Melt the butter in a medium bowl; let cool slightly. Add the cottage cheese, milk, pumpkin, eggs, and vanilla and whisk to combine.
In a large bowl, whisk the flour, sugar, pumpkin pie spice, baking powder, baking soda, and salt. Fold in the pumpkin mixture and stir until just combined.
Scrape the batter into the prepared baking sheet; smooth with a spatula. Top with chocolate chips (feel free to add more if you want!)
Bake until puffed and a toothpick comes out clean, 10 to 12 minutes. Brush with a little melted butter, if desired (just avoid the chocolate chips since they’ll be melty).
Slice into 12 pieces and serve with more butter and maple syrup.
