Cream the butter and sugar until smooth and creamy. Whisk in the maple syrup, soy milk and vanilla paste.
In a second bowl, mix the flour, bicarbonate of soda, salt and spices.
Add the dry ingredients to the dry and fold gently with a spoon.
Cover the bowl with cling film and leave to chill in the fridge for 30 minutes.
Meanwhile prep the ice cream by blitzing the frozen bananas and cornstarch in a food processor until soft and creamy, but still holding some shape. Spoon 6 discs of ice cream, roughly the same diameter as your cookies, onto a plate lined with parchment paper and place in the freezer.
Line two baking trays with parchment paper and preheat the oven to 190C/ 170C fan.
Once chilled, use a ice cream scoop to form 12 balls of cookie dough, and place on the baking tray.
Bake the cookies for 10 minutes, they will be soft in the middle and slightly crisp on the edges.
Leave the cookies to firm up on the tray for 5 minutes, then slide onto a wire cooling rack and leave for a further 10 minutes. Pop the cookies in the fridge and leave to chill completely, around half an hour.
Remove the cookies and banana ice cream from the chiller. Sandwich the ice cream discs between the cookies. Best eaten immediately or return to the freezer to enjoy at a later date.