I always start by preheating my oven to 350°F so it's fully heated by the time my batter is ready. I line my 8x8-inch pan with parchment paper, leaving a little overhang on the sides. This little trick makes lifting the brownies out later so much easier and mess-free.
In a large bowl, I whisk together the pumpkin puree, oil, sugar, and vanilla extract until the mixture looks smooth and glossy. I make sure there are no lumps of pumpkin left behind. This forms the moist base that keeps the whole batch fudgy.
Next, I add the flour, cocoa powder, baking powder, salt, and cinnamon directly into the same bowl. I whisk gently until just combined, being careful not to overmix. Overmixing at this stage is what makes brownies turn out tough instead of tender.
I fold in most of the chocolate chips with a spatula, saving a small handful to sprinkle on top later. This gives every bite little pockets of melty chocolate, which honestly makes the whole recipe feel extra indulgent.
I pour the thick batter into my prepared pan and spread it evenly using my spatula, pushing it right into the corners. I sprinkle the reserved chocolate chips over the top so they get slightly toasted and shiny as they bake.
I bake mine for 28-30 minutes, checking at the 25-minute mark with a toothpick inserted in the center. I'm looking for a few moist crumbs, not a completely clean toothpick, since that's the sign of a fudgy texture rather than a dry one.
This is the step I always want to skip, but never do. I let the brownies cool in the pan for at least 15-20 minutes before lifting them out and slicing into squares. Cutting too early causes the center to fall apart.