Combine red wine vinegar, shallot, raspberries, raspberry preserves, and honey in a blender pitcher; blend until smooth.
With the blender running, slowly stream in the olive oil and blend until the dressing emulsifies. Season to taste with salt and pepper, then pour it through a fine-mesh sieve into a small pitcher, pressing with the back of a spoon to catch the seeds. Serve right away or cover and refrigerate for up to one week.
Notes
If you don't mind seeds, you can skip the step of straining them out.
The recipe makes about 1 1/2 cups dressing. Refrigerate leftovers in an airtight container and use within one week.