Preheat the oven to 350°F (175°C) and grease a 9-inch baking pan.
In a bowl, whisk together flour, baking powder, baking soda, and salt.
In another bowl, combine sugar, butter, plant-based milk, vanilla, and apple cider vinegar.
Add the wet ingredients to the dry ingredients and mix until smooth.
For the streusel topping, combine pecans, sugar, flour, cinnamon, and butter. Mix until crumbly.
Pour the batter into the pan and sprinkle the streusel topping evenly over it.
Bake for 35-40 minutes or until a toothpick comes out clean.
Let it cool for 10 minutes, slice, and enjoy.