You already have all these ingredients in your house, so there's no excuse not to make this today. Actually, you should make it in a few days, because you want your bananas to be super-ripe, like fully brown—the same way you want them for banana pudding, banana bread, or banana cream pie. There isn't anything you need to worry about for presentation for this one, because everything just gets blended up together. This drink is fantastic in the late afternoon. When those pre-dinner hunger pangs hit, this will tide you over and give your mood a little lift, too.
In a blender, combine the jam, ice, and milk and blend on medium speed until smooth.
Add toppings to a glass, if using, and pour the drink into the glass.
Preheat the oven to 400°F.
Peel the bananas and slice them in half lengthwise. Cut those halves into 1/2-inch thick pieces and place them in a mixing bowl. Add the brown sugar, lemon juice, and cinnamon, and toss thoroughly to coat the banana pieces. Line a baking sheet with parchment paper, and spread the bananas out in an even layer on the parchment.
Roast the bananas until they are caramelized, about 15 minutes. Take them out of the oven and set them aside to cool. Once the. bananas are cool, place them in a food processor and process until smooth. Add salt to taste.
The banana jam will keep in the fridge for 1 week.