Preheat oven to 180C. Line a 9-inch loaf pan with baking paper and grease with coconut oil.
First, make the vegan buttermilk -in a small bowl whisk together almond milk, lemon zest, and lemon juice. Set aside for 5 minutes.
Now whisk together the sugar and olive oil in a large bowl until creamy. Pour in the buttermilk mixture. Mix to combine.
In another bowl, combine the flours, baking soda, baking powder, and salt. Fold into buttermilk mixture and gently stir until combined.
Now pour the batter into the pan and smooth the top. Bake until a toothpick inserted comes out clean–approx 45 minutes.
Remove from oven and cool at least 10 minutes.