Grease a 5-by-9-inch loaf pan and line with heavy-duty plastic wrap. Using a food processor, puree the raspberries; strain. Discard the seeds.
In a small bowl, mix the fruit pectin with 2 tablespoons sugar.
In a medium saucepan, heat the raspberry puree over medium-high heat until simmering. Set a candy thermometer in the pan. Gradually whisk in the pectin mixture and bring to a boil, whisking. Add 1/2 cup sugar and, whisking constantly, return the mixture to a boil. Add another 1/2 cup sugar and, whisking constantly, return the mixture to a boil again. Add the corn syrup and boil until the mixture reaches 225 degrees , about 10 minutes. Whisk in the lemon juice. Let cool slightly, then transfer to the prepared pan; let sit until firm, 12 hours or overnight.
Turn the jellied candy out of the pan and onto a cutting board. Trim off and discard the edges and cut the candy into 1-by-3/4-inch rectangles. Place the remaining 1/2 cup sugar in a shallow bowl. Toss the jellied candy in the sugar to coat.