With the rack in the middle position, preheat the oven to 180°C (350°F). Line an 18 x 28-cm (7 x 11-inch) cake pan with parchment paper, letting the paper hang over 2 opposite sides.
In a bowl, combine the flour and salt.
In another bowl and using an electric mixer, cream the butter with the sugar and vanilla on medium speed until light and fluffy. Add the egg and beat until smooth. Using a wooden spoon, stir in the dry ingredients and cranberries. Press into the bottom of the pan. Bake until light golden brown, about 25 minutes.
Meanwhile, in a saucepan, whisk together all the ingredients. Cook over medium heat, whisking constantly, until the mixture begins to thicken. Pour onto the crust. Bake for about 12 minutes. Let cool slightly. Cover and refrigerate for 2 hours.
Unmould and cut into 12 bars.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.