With the rack in the middle position, preheat the oven to 375°F (190°C).
In a saucepan, bring the syrup, cream, water and ¾ cup (160 g) brown sugar to a boil, stirring continuously. Simmer for 2 minutes. Pour into an 8-cup (2 litre) soufflé dish.
In a bowl, combine the flour, starch, baking powder, and salt.
In another bowl, cream the butter and the remaining brown sugar with an electric mixer. Add the egg yolks and stir to combine. At low speed, add the dry ingredients alternately with the milk.
In another bowl, beat the egg whites with the cream of tartar until stiff peaks form. Gently fold the egg whites in the batter with a spatula. Wit an ice cream scoop or large spoon, spread the batter over the hot syrup.
Bake for about 40 minutes or until a toothpick inserted in the centre of the cake comes out clean. Serve warm or cold.
Stir gluten-free flours before measuring and be careful not to compact them.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.