Preheat oven to 375 F. Coat a 10-inch tart pan with removable bottom with cooking spray. Set aside.
To make the crust, sift the flour and salt onto a working surface and mix in the sugar. Work the yeast thoroughly into the mixture. Make a well in the center and add eggs and butter. Draw the flour into the center with the fingertips. Mix to create a supple dough, adding a little water if necessary. Knead very lightly and leave covered at room temperature for 2 hours.
To prepare the filling, first blend the cornstarch with a little of the milk. Beat in the eggs and sugar. Gradually stir in the remaining warm milk. Pour into a saucepan and place over low heat. Cook gently, whisking constantly, until the custard thickens. Strain if necessary.
Roll out the pastry thinly and use it to line prepared pan. Arrange the cherries in the tart pan and carefully pour in the cooled custard. Bake for 20-30 minutes or until the pasty is golden and the crust is set. Serve warm or cold.