1.5cups gluten-free self raising/self-rising flour*see below for substitutes
Heat oven to 175C/350F.
Grease and line a cake tray (I tend to use a rectangular brownie pan)
Cream butter and sugar together, then add eggs and vanilla.
Add mashed banana to wet mixture and combine.
Gently fold in the flour, soda and milk until most of the lumps are gone. Be careful not to overmix here as it can affect the 'fluffiness' of the banana cake.
Bake in oven for 30-35 minutes or if using a round dish, you may need to add another 5 minutes. Either way, check on the cake at 30 minute mark and test with a skewer. If the skewer comes out clean and the cake gives a slight 'bounce' when touched on top, it's ready!
Allow to cool completely.
If you don't have gluten-free self-raising/self-rising flour on hand, you can substitute it with gluten-free plain/all-purpose flour instead. However, you will also need to add 1 tsp of baking powder for this recipe to allow the cake to rise adequately. Ideally though, use a self-raising/self-rising flour where possible.