Preheat the oven to 350¡ãF and spray an 8x8-inch baking pan with nonstick cooking spray. Set aside.
Place the strawberries between several layers of paper towels and press firmly to wick out some of the moisture. Set aside.
In a medium bowl, whisk the flour, baking powder, and salt together. Set aside.
In a large bowl, stir the butter, brown sugar, and white sugar together. Add the egg and vanilla and stir until incorporated. Add the dry ingredients and stir to combine. Add the strawberries and stir.
Spread the mixture into the prepared pan and bake for 28 to 33 minutes or until golden brown and set. Allow to cool completely.
Make the glaze by stirring the powdered sugar, strawberry jam, and water together until smooth. Spread over the blondies. Allow the glaze to harden overnight, if desired. Slice and serve. Store in an airtight container at room temperature for up to 3 days or in the refrigerator for up to 5.