• Preheat the oven to 350°F/176°C. Arrange a rack in the middle or bottom third of the oven. Line a 9x5-inch loaf pan (23x13 cm) with parchment paper, letting the excess hang over the long sides to form a sling.
• Stir the vinegar into the milk and set aside for a few minutes. This is the “buttermilk.”
• Pour the aquafaba into a small bowl. Using a handheld electric mixer, whip the aquafaba on medium speed for 45 seconds, or until uniformly foamy.
• In a large mixing bowl, add the brown sugar and oil. Mix using the electric mixer or a whisk until well combined. Add the whipped aquafaba and mix until well incorporated. Add in the “buttermilk,” pumpkin puree, maple syrup, and vanilla. Mix until smooth and the ingredients are very well incorporated (this is important so you don't overmix).
• In a medium bowl, combine the flour, baking soda, baking powder, salt, and Homemade Pumpkin Spice. Whisk well to ensure the leaveners and spices are evenly distributed.
• Add the dry ingredients to the wet ingredients and gently stir using a silicone spatula or wooden spoon until just barely combined and no flour pockets remain, then stop mixing! The batter doesn’t need to be totally smooth—some lumps are normal. It should be quite thick and almost fluffy at this point.
• Pour the batter into the prepared loaf pan and smooth out the top.
• Bake for 55 to 60 minutes, or until a toothpick inserted into the top sides of the cake comes out mostly clean with just a few moist crumbs.

  I like to check the bread at 53-55 minute mark. To test if it's done, insert a toothpick downwards at an angle (not just straight down). If the toothpick has batter that is a bit gooey, bake for 5-10 more minutes. If you’re worried about the top browning too much, loosely tent the pan with foil.
• Transfer the pan to a wire rack and cool for 10-15 minutes. Then, using the parchment paper handles, remove the bread from the pan and cool on the rack for at least 30 minutes before serving.

  Serve plain, or with the Cream Cheese Icing or the Maple Tahini Icing and scatter with handful of pepitas or chopped pistachios. See Note 5 for storage instructions.

Cream Cheese Icing (optional)

• To a medium mixing bowl, add the softened butter. Beat on low speed with an electric hand mixer until smooth. Add the cream cheese and beat until well incorporated and creamy.

  Add HALF of the powdered sugar, mix on low speed to combine, and then add the rest of the sugar. Mix until well combined and fluffy, scraping down the sides as you go. Add the vanilla, salt, and lemon juice and mix until smooth. If too thick, add a splash of plant-based milk. If too thin, briefly refrigerate.

Maple Tahini Icing (optional, see Note 6)

• Sift the powdered sugar into a large bowl (sifting gets rid of the lumps in the sugar). Add in the tahini, milk, and maple syrup. Whisk to combine until the icing is thick but pourable. If too thin, add more sugar. If too thick, add more milk. Pour icing ONLY on the amount of bread you plan to eat (or serve it on the side).