Preheat oven to 350 degrees F. Process cookies in the food processor. Add melted butter and 1 tablespoon of water. Continue processing until combined. Press crumb mixture into a 9-inch pie plate that has been coated with cooking spray. Bake 9-11 minutes. Remove from oven and cool on a rack.
Place 2 tablespoons water in a small bowl. Sprinkle gelatin over water, stir until dissolved. Set aside. Place half & half, 1/4 c of sugar, cocoa powder, egg and vanilla in a small saucepan. Cook, stirring with a whisk, over medium-low heat until thickened - approximately 160 degrees F. Remove from heat. Stir in gelatin mixture and chocolate chips. Chill chocolate mixture to room temperature.
Place egg whites in a medium mixing bowl. Beat on high speed with an electric mixer until frothy. Add remaining 1/4 c of sugar. Beat until soft peaks form. Fold egg whites into the cooled chocolate mixture. Pour mousse into pie shell. Refrigerate until mousse is set - about 4 hours. Garnish with strawberries. Slice to serve.