Rub butter into flour and salt with your finger tips. Add the egg and water, and mix until just combined. Chill to harden. Work out dough to soften onto a floured countertop. Roll out into a 3mm thick disk. Gently prick with a fork, and lay dough over a greased tart pan and shape into a pie. Remove excess dough and chill for up to 3 days; uncovered.
Blind-bake tart shell for 30 min at 350ºF/180ºC with pie weights. Remove pie weights, and set aside.
*Apricot can be subbed for other dry fruits such as figs, prune, dates... In a saucepan, bring to a boil milk with sugar and vanilla bean and seeds. Shut off the heat, cover and let infuse for 20 min. Meanwhile, cut apricot into julienne and then small cubes. Melt butter in a skillet, stir in rice and apricots for 2 minutes. Pour one-third of the hot milk and start cooking risotto stirring continuously on medium-low heat. Risotto rice will begin releasing its starch which create a rich creamy sauce. Add remaining hot milk as it goes. Expect this sweet risotto version to take longer than the 18/20 minutes usually required. Indeed, it should rather take 35/40 minutes. Transfer the cooked risotto in a pastry bowl.
About 10 min before the risotto is cooked through: In a stand mixer fitted with the whisk attachment, begin to whip egg whites with one-third of the sugar on medium speed; keep it on foamy stage. When ready, set on high and beat meringue to firm peaks; adding remaining sugar. Turn the oven on to 350ºF/180ºC. Fold egg yolks in the risotto first, then the meringue. Fill up pre-baked tart shell generously, or a baking dish – pop in the oven right away.
Bake for about 25 minutes. Note that and because of the rice, it wont puff up as a classic soufflé – Better served right away, or lukewarm. Enjoy!