2Toss tomatoes, shallots, garlic, olive oil, sage, and rosemary together in large bowl until everything is coated in olive oil; season with salt and black pepper. Spread the tomato mixture into a baking dish.
3Roast in preheated oven until the garlic cloves are soft, about 20 minutes.
4Blend the tomato mixture with balsamic vinegar in a blender until smooth.
5Stream canola oil into the blended mixture with the blender on until the mixture emulsifies into a dressing.