In a blender, combine the speculoos, milk, and banana and mix until combined, 1 minute. Add the ice cream and blend until mixed but still thick, 1 to 2 minutes. Pour some into pint/parfait glasses alternating with dollops of preserves, creating layers. Using a long skewer, or a knife, swirl the jam into the shake, have fun with it. Garnish with a strawberry on the edge of the glass and watch the love in your child's eyes shine.