Preheat oven to 350°F (176° C). Line a square 8x8 inch baking pan with parchment paper. Set it aside. Melt 1 stick of vegan butter and then allow it to cool for a few minutes.
In a large bowl, whisk together the melted butter and brown sugar until well blended.
Add apple sauce or egg replacer of your choice and vanilla extract and whisk to combine.
Add in the flour, cornstarch, and salt, stirring with a wooden spoon until just blended and no dry flour spots appear.
Stir in 3/4 cup white chocolate chips.
Scoop the batter into the prepared baking dish and press gently into corners to form an even layer.
Dollop the top with small spoonfuls of raspberry jam. Using a toothpick, swirl the jam into the top of the bars. Simply drag the stick around the top to make a swirling pattern. Sprinkle the top with 1/4 more white chocolate chips.
Bake the blondies at 350° F (176° C) for 25 minutes, or until the top looks set and the edges are golden brown.
Allow the blondies to cool completely in the pan before lifting them out with the parchment paper. Cut the blondies in half in each direction then cut those halves in half again to get 16 equal squares.
Notes
Blondies are supposed to be chewy and a little gooey with a similar texture to fudgy brownies. They don't have baking powder or baking soda which would cause them to rise and give them a cakey texture.
Allow the blondies to cool completely before cutting.