Preheat your oven to 350 degrees F (175 degrees C). While the oven is heating, spray an 8×8-inch baking dish with non-stick cooking spray to prevent sticking. Set the prepared dish aside until ready to use.

In a large mixing bowl, combine the flour, sugar, baking soda, baking powder, salt, and pumpkin spice blend. Mix thoroughly with a whisk or fork to ensure all ingredients are evenly distributed.

Make three wells in the mixed dry ingredients: two smaller ones and one larger. Pour the vanilla extract and vinegar into the two small wells, and the canola (or vegetable) oil into the large one. Next, pour the pumpkin puree and water over the entire bowl. Using a whisk, mix everything together until the batter is smooth and well blended with no dry patches remaining. I always make sure not to overmix—just whisk until everything is incorporated; this keeps the cake nice and tender.

Pour the smooth batter into the prepared baking dish, spreading it evenly with a spatula. Place the dish on the middle rack of your preheated oven and bake for 40 minutes. Start checking for doneness at 35 minutes by inserting a toothpick into the center—if it comes out clean or with just a few crumbs, the cake is done. Some ovens may require up to 45 minutes.

Once baked, remove the cake from the oven and let it cool to room temperature in the baking dish. For serving, you can top it with your favorite vanilla frosting, icing, or simply dust with powdered sugar. I personally love serving this cake with a light dusting of powdered sugar and a cup of coffee for an autumn treat!