Carefully core the cabbage by cutting around the stem with a sharp knife and gently peel away the leaves. Bring a large pot of water to a boil, then blanch the leaves in boiling water for 2-3 minutes until they become bright green and pliable. Drain and set aside to cool slightly.
While the cabbage cools, mash the silken tofu in a large bowl until smooth. Add the cooked rice, finely chopped onion, minced garlic, dried dill, thyme, smoked paprika, salt, and pepper. Mix everything thoroughly until a creamy, cohesive filling forms.
Lay a blanched cabbage leaf flat on your work surface. Spoon about 2-3 tablespoons of the filling near the stem end. Fold in the sides, then roll tightly from the stem to the tip, pinching gently to seal the filling inside. Repeat with remaining leaves and filling.
Pour the vegetable broth into a deep skillet or Dutch oven. Arrange the cabbage rolls seam-side down in the broth, nestling them closely together. Cover with a lid, then bring the broth to a gentle simmer over medium heat, around 80°C (176°F). Cook for 30-35 minutes until the leaves are tender and the filling is heated through.
After simmering, carefully lift the cabbage rolls with tongs and transfer them to a serving platter. Drizzle a little of the cooking broth over the rolls to keep them moist and flavorful. Let them rest for 5 minutes to allow the flavors to meld.
Serve the cabbage rolls warm, garnished with fresh herbs if desired. The leaves should be tender with a slight smoky aroma, and the filling creamy and flavorful. Enjoy this comforting, plant-based take on a classic dish!