Prepare the base: In a medium saucepan, combine raspberries, apple cider vinegar, brown sugar, honey, lemon juice, salt, and pepper. Stir everything together gently over medium heat. As the mixture warms, the raspberries will start to break down and release their juices, creating a thick, fragrant base.

Add the smoky heat: Chop the chipotle peppers finely and add them to the saucepan along with the adobo sauce. Stir well so the smoky flavor blends into the sweetness of the raspberries. Let it cook for about 10–12 minutes, stirring occasionally to prevent sticking or burning at the bottom.

Simmer and adjust flavor: Taste the sauce at this point — if you want more sweetness, add a bit more honey; if you prefer it spicier, stir in another half pepper or an extra spoon of adobo sauce. Let it continue simmering gently for another 5–7 minutes until the flavors meld and the sauce thickens slightly.

Optional thickening: For a thicker, glossy finish, whisk in the cornstarch slurry (cornstarch and water mixture). Continue stirring for 1–2 minutes until the sauce thickens to your liking.

Blend and strain: Remove from heat and let it cool slightly. Blend the mixture using an immersion blender or a countertop blender until smooth. For an elegant, restaurant-style texture, strain it through a fine-mesh sieve to remove seeds and pulp — this step gives you a silky, velvety sauce.

Cool and store: Let the sauce cool completely before transferring it to a glass jar or airtight container. Store in the refrigerator for up to 2 weeks.