Rinse raspberries and place in a small saucepan. Roughly mash with a potato masher or fork.
Add sweetener if desired, based on the natural sweetness of your berries.
Heat the mixture on low for 5 minutes, stirring occasionally to intensify flavors.
Strain through a fine mesh strainer to remove seeds (optional if you prefer texture).
Allow raspberry mixture to cool completely.
Whisk in vinegar, olive oil, salt, and pepper until well combined.
Taste and adjust seasoning or sweetness as needed.
Refrigerate for 1-2 hours before using for best flavor development, though it can be used immediately.