Place tofu in a colander and let sit for 10 minutes to drain the liquid.
Crumble the tofu into the food process and add peanut butter, milk, sweetener and vanilla to the food processor and blend until thoroughly combined and creamy, about a minute or two.
Spoon mousse into four ramekins or other individual serving dishes, cover with plastic wrap and refrigerate for an hour or more.
When ready to serve, add a few slices of banana and top with a sprinkling of chocolate chips or discs. Whipped coconut cream would also be a welcome addition.