Preheat the oven to 350ºF. Line a loaf pan with parchment paper and set aside.
Add the dry ingredients to the bowl and whisk to combine. In a separate bowl, beat together the eggs, mashed banana, oil, syrup, vinegar and vanilla and beat until smooth.
Pour the wet ingredients into the dry and fold together. Once combined, fold in the apple and pecans.
Transfer batter to the prepared loaf tin, sprinkle with additional chopped pecans and turbinado sugar (if using). Bake on the center rack for 45 - 50 minutes until the top has turned golden brown and a cake tester inserted into the center comes out clean.
Cool in the pan for 1 hour then transfer to a wire rack and cool completely before slicing.