Preheat oven to 325°F. Spray a 9-inch tart pan with non-stick spray.

Combine vanilla wafer crumbs and sugar in a bowl, then pour melted butter and mix well.

Press the mixture into the tart pan, covering the bottom and sides, and bake for 15 minutes. Let cool.

In a small bowl, sprinkle gelatin over cold water and let sit for 5 minutes.

Whisk cornstarch and sugar in a saucepan, then add champagne and heat until just boiling, stirring constantly.

Melt gelatin, stir into champagne mixture, then let cool to room temperature.

Whip heavy cream and powdered sugar until thickened.

Fold mascarpone cheese into whipped cream, then gently mix in the cooled champagne mixture.

Pour filling into cooled crust and refrigerate for 2-3 hours until set.

Combine champagne, cornstarch, and sugar to make the glaze. Microwave until thickened, then let cool slightly.

Arrange sliced strawberries on top of tart filling, then brush with cooled glaze.

Refrigerate until ready to serve.