Instructions for the loaf

• Preheat oven to approximately 190 degrees Celsius and grease a large loaf tin. If you don't have a large one, use two smaller ones.
• In a stand mixer fitted with the paddle attachment or in a large bowl with a handheld mixer, beat butter and sugar until smooth.
• Add banana and beat for 20 seconds.
• Add flour, milk and vanilla in alternating batches until just combined.
• Add sultanas and walnuts and mix until just combined. 
• Pour batter into prepared tin(s) and hit the base against your kitchen counter to remove any air bubbles.

Instructions for the crumble

• Combine all ingredients until a crumble forms.
• Sprinkle over prepared batter, cover with foil or baking paper and place in the oven.
• Cook for approximately one hour (or less if you're using two tins), remove foil and cook for a further 30 minutes. The cooking time may vary depending on your oven so pay close attention and check by inserting a skewer throughout.
• Remove from the oven, cut into pieces and serve warm or at room temperature with vegan butter or almond butter.