The homemade cherry-berry sauce in this recipe gets depth and heat from canned chipotle chile in adobo (and a tiny bit of the adobo sauce) -- no ketchup in this BBQ! The fresh fruit brings a brightness that pairs wonderfully with the smoky, falling-off-the-bone-tender ribs.
For the ribs: Position an oven rack in the center and preheat the oven to 325 degrees F. Peel the thin membrane off of the back side of the ribs and discard.
In a small bowl, combine the brown sugar, coriander, paprika, mustard, 1 tablespoon salt and 1/2 teaspoon black pepper. Sprinkle evenly all over both sides of the ribs. Wrap each rack of ribs in a separate piece of aluminum foil and place on a baking sheet. Bake for 1 1/2 hours.
For the blueberry-cherry BBQ sauce: Meanwhile, add the olive oil to a medium saucepan and place over medium heat. Add the garlic and shallot and cook, stirring frequently, until softened, 3 to 4 minutes. Add the coriander and cinnamon and cook, stirring, until fragrant, about 1 minute more. Add the cherries, blueberries, chicken broth, cider vinegar, brown sugar, chipotle chile and adobo sauce. Season with salt and pepper. Bring to a boil, stirring to dissolve the sugar. Reduce the heat and simmer, mashing the cherries and blueberries with a potato masher halfway through to release their juices, until the fruit is softened and the mixture is saucelike, about 15 minutes.
Let the sauce cool briefly. Then transfer to a blender and blend until smooth (see Cook's Note). Return to the saucepan and stir in the Dijon. The sauce should nicely coat the back of a spoon. If the sauce is too thin, bring it back to a simmer and continue to reduce until the correct consistency. Reserve 1 cup in a bowl for glazing. Set aside the remainder in the saucepan and cover to keep warm.
Once the ribs have baked 1 1/2 hours, carefully place each rack on its own baking sheet. Unwrap the ribs from the foil, keeping the foil on the baking sheet as a liner of sorts. Brush the ribs with the reserved 1 cup BBQ sauce and bake until nicely browned and tender when pierced with the tip of a sharp knife, basting once more with sauce halfway through, about 30 minutes.
Preheat the broiler. Brush another layer of sauce on each rack of ribs and place one of the racks under the broiler until the sauce is caramelized and lightly charred, 3 to 4 minutes (be sure to watch as all broilers vary!). Repeat with the second rack of ribs.
Transfer the reserved sauce from the saucepan to small bowls. Slice into individual ribs and serve with the sauce for dipping.
When blending hot liquid, first let it cool for five minutes or so, then transfer it to a blender, filling only halfway. Put the lid on, leaving one corner open. Cover the lid with a kitchen towel to catch splatters, and pulse until smooth.