Preheat your oven to 350°F (175°C). Gather your mixing bowls and a baking sheet lined with parchment paper.

Cream together softened unsalted butter and granulated sugar until light and fluffy, about 3–5 minutes. Add in the large egg and pure vanilla extract, mixing until fully incorporated.

Incorporate the strawberry powder into your creamy mixture, then sift in the flour and salt while mixing until a smooth dough forms.

Cover the cookie dough with plastic wrap and chill in the refrigerator for about 30 minutes.

Roll out the dough to about 1/4-inch thickness. Cut out the desired boat shapes and transfer them to your prepared baking sheet.

Bake the cookie shapes for 12–15 minutes, until set and slightly golden at the edges. Let them cool completely on a wire rack.

While your cookies cool, beat together the mascarpone cheese, heavy cream, powdered sugar, and a splash of vanilla extract until smooth and fluffy.

Pipe the mascarpone cream filling into the cool indents of each cookie. Arrange sliced fresh strawberries artfully on top.

Mix the strawberry jam with a little water and use a pastry brush to gently coat the fresh strawberries.

Sprinkle optional shortbread cookie crumbs over the topped Strawberry Cookie Boats and refrigerate for at least 30 minutes before serving.