Cut bananas in half lengthwise, then width-wise. Layer in the bottom of a 1-1/2 quart slow cooker. With a wire whisk, combine the packed brown sugar, melted butter, liqueur and vanilla extract. Pour over bananas in slow cooker. Cook on low for 2 hours.
Sprinkle chopped pecans and coconut over bananas in slow cooker. Cover and cook 1/2 hour longer or until heated through.