In a large bowl, cream together butter and sugar until light and fluffy. Add egg and vanilla extract, beating until well combined. Mix in the strawberry powder to achieve a pink color.

Gradually add flour and salt, mixing until just combined. Form the dough into a ball, wrap in plastic wrap, and refrigerate for 30 minutes.

Preheat oven to 350°F (175°C). Roll out the dough on a floured surface to 1/4 inch thickness. Cut into boat shapes or use an oval cookie cutter. Place on parchment-lined baking sheets.

Use your thumb or the back of a spoon to create an indentation in the center of each cookie, forming a boat-like shape. Bake for 12-15 minutes until set but not browned. Cool completely.

Beat mascarpone cheese, heavy cream, powdered sugar, and vanilla extract until smooth and thick. Transfer to a piping bag fitted with a star tip.

In a small saucepan, heat strawberry jam with water until melted and smooth. Allow to cool slightly.

Pipe cream filling into the cookie boats. Arrange sliced strawberries on top of the cream. Brush strawberries with the jam glaze.

Sprinkle shortbread cookie crumbs around the dessert for garnish. Refrigerate until ready to serve, but bring to room temperature about 15 minutes before serving for best flavor.