HEAT 1 tablespoon of the oil and the butter in a saucepan and cook the onion and celery for 6 minutes. ADD 1 clove of finely chopped garlic, the oregano and thyme and cook for 1 minute. ADD the flour and cook for 1 minute, stirring to combine. REMOVE from the heat and add the stock gradually, stirring constantly, until slightly thickened. RETURN to the heat and add the tomatoes, tomato paste, salt, and pepper. BRING to a boil, lower the heat to medium and simmer, uncovered, for 10 minutes. WHILE the soup cooks, preheat a large frying pan over a medium-high heat. BRUSH the bread slices evenly with 1 tablespoon of oil on both sides. PLACE the slices in the pan and cook until both sides are crisp and browned. TRANSFER the toasts to a plate and, when cool enough to handle, rub one side of each slice with the cut side of 1 peeled and halved garlic clove. REMOVE the soup from the heat and puree in a blender or with a stick blender. RETURN the soup to the saucepan, stir in the milk, and reheat gently. SERVE in bowls with the garlicky toasts on the side.