- Spray a 9-inch tart pan with removable bottom with cooking spray.
- Line the tart pan with the pie crust.
- Put the almond paste in the bowl of an electric mixer and beat until smooth.
- Add the egg, sugar, butter, flour, vanilla and almond extracts, and salt.
- Beat on medium-high speed until smooth.
- Scrape the mixture into the prepared tart pan.
- Top with the grapes and bake for 30 -35 minutes or until golden brown. Let cool in the pan.
- Remove the outer ring, dust with powdered sugar, and serve.