Roasting the garlic softens and sweetens the strong flavor.
- Slice 1/4” off top of garlic head. Wrap garlic in foil and bake 350° until soft when pressed (about 1 1/4 hours). Carefully remove garlic from foil; transfer to a rack and let stand until cool enough to handle.
- Meanwhile arrange bread slices slightly apart in a large, shallow baking pan. Broil about 6 inches below heat, turning once until golden on both sides (about 5 minutes). Let cool on a rack.
- Squeeze garlic cloves from skins into a food processor or blender. Drain beans, reserving liquid. Rinse beans and add to processor along with basil, parsley, lemon juice, tahini, and salt. Whirl until coarsely pureed. If necessary, add enough of the bean liquid to make mixture spreadable.
- Top toast slices with bean mixture; arrange tomato slices on top.
Makes 8 servings.