Heat the oven to 425°F. Toss tomatoes, onion and garlic with oil and roasting salt on a rimmed baking sheet; roast for 25 to 30 minutes until softened and browned at the edges.
Blend the roasted vegetables and their juices smooth with an immersion blender in a deep heatproof container, keeping the blade submerged.
Brown beef in a large skillet for 7 to 8 minutes, breaking it into fine crumbles, until it reaches 160°F. Drain excess fat.
Add the fresh tomato sauce, vinegar, brown sugar, Worcestershire, mustard, pepper and filling salt. Simmer uncovered for 12 to 15 minutes until thick enough to mound on a spoon.
Toast the split rolls in the still-warm oven for 3 to 4 minutes, divide the filling among them and serve.