Place raspberries in a food processor and pulse until completely pureed. Place raspberry puree in a fine-meshed sieve set over a medium bowl, pressing to extract all the juice from the puree. Discard the seeds and pulp.
Pour the strained puree into a medium saucepan and add the lemon juice and sugar. Bring mixture to a boil, and cook for 2 minutes, or until the mixture slightly thickened. Remove from the heat and cool puree completely.
Cream together the butter, honey, salt, and cooled puree until smooth and well blended. (This may take up to 5 minutes on high speed.) Place butter in molds or onto sheets of plastic wrap and roll into logs. Refrigerate until well chilled and firm.
Yield: 1 1/2 cups butter