Preheat oven to 350F. Grease or spray a standard bread pan. Whisk non-dairy milk and lemon juice together until bubbly and set aside. In a medium mixing bowl, cream pumpkin, sugar, syrup and extract together. In a large bowl, whisk pumpkin pie spice, flour, baking soda and baking powder together. Pour wet mixture into dry mixture and stir until just combined. Pour into bread pan, using a spatula to evenly distribute and smooth out the top. Grab a large piece of aluminum foil and make a tent over the pan. Bake for 1 hour, or until a toothpick inserted in the center comes out clean. If using icing, prepare while bread is baking. Once the bread has cooled but is still slightly warm, gently remove it from the pan and on to a serving plate.