For the cream puffs: Preheat the oven to 425 degrees F. Line a rimmed baking sheet with parchment paper.
Put the butter, granulated sugar, salt and 3/4 cup water in a medium saucepan and bring to a boil over medium heat. As soon as it boils, take off the heat and add the flour. Mix vigorously with a wooden spoon until the mixtures comes together and pulls away from the sides of the pan, about 1 minute. Transfer the mixture to a large bowl. Beat with an electric mixer at medium speed until slightly cooled. Add the eggs 1 at a time, beating well after each addition. After adding the last egg, beat on medium speed for 1 minute. Use a 1 1/2-inch cookie scoop to place rounds about 1/2 inch apart onto the prepared baking sheet.
Bake the cream puffs for 10 minutes, then reduce the oven temperature to 325 degrees F and continue to bake until golden brown and hollow-sounding when tapped, 20 to 25 minutes. Transfer to a rack and cool completely, then use a serrated knife to cut the puffs in half.
For the filling: Beat the cream, mascarpone and confectioners' sugar with an electric mixer at medium-high speed until it just holds stiff peaks, then gently fold in the jam.
When ready to serve, use a large spoon to dollop the cream on the bottom half of the puffs and add 1 raspberry to each. Then top with the other half of the puff.