In the US, white chocolate must contain at least 20 percent cocoa butter. But for better flavor, look for something with an even higher percentage. Avoid white chocolate with fillers like oil and artificial flavor. A good white chocolate has a gorgeous milky flavor with a floral essence that can evoke both cocoa and vanilla.
For the crust: Preheat the oven to 350 degrees F. Line a 9-inch square baking pan with parchment paper, leaving a 2-inch overhang on 2 sides.
Add the graham cracker crumbs, sugar and salt to the prepared baking pan and toss with a fork to combine. Add the butter and toss until evenly moistened. Spread the crumb mixture out and pat down to an even layer.
Bake until the crust is toasted and fragrant, about 10 minutes. Transfer to a rack to cool completely. Lower the oven temperature to 300 degrees F.
For the cheesecake: In a large bowl using an electric mixer, beat the cream cheese, sugar and salt until fluffy and smooth, 3 to 4 minutes. Beat in the white chocolate until well combined. Beat in the eggs one at a time, just until combined; do not overmix once you've added the eggs. Transfer the cream cheese mixture to the cooled crust and spread out to an even layer.
Drop the raspberry jam in dollops all over the top of the cheesecake. Then, using a toothpick, swirl the jam and the cheesecake batter decoratively.
Bake until the cheesecake is set about 2 inches around the edges but is still a bit jiggly in the center, 25 to 30 minutes. Transfer to a rack to cool for about an hour, then wrap with plastic and refrigerate until completely cold, at least 6 hours.
Use the parchment to lift the cheesecake onto a cutting board and cut into pieces to serve.