Preheat the oven to 250F. Line a baking sheet with waxed paper. Spread the carrot over the paper; top with the onion. Bake for about 30 minutes to dry out the vegetables. Cool on the baking sheet on a wire rack. Reduce oven temperature to 350F. In a large bowl, combine the dried carrots and onion with the mushrooms, tomatoes, and basil. Add the unbleached and semolina flours, the cheese, baking powder, and salt; mix well with a fork. Make a well in the center. Add the water and oil. Mix with a wooden spoon until the dough begins o gather. (If the dough is slightly dry add another tablespoon of water.) Knead with hands into a ball. Roll the dough between the palms of hands into a thick rope. Wrap in waxed paper and chill for 15 minutes. After the dough has chilled, cut it into 12 equal pieces. Working with one piece at a time (keep the remaining dough covered), shape into a ball. Place the ball of dough between two pieces of lightly- floured waxed paper and roll out to a 4 to 5 inch circle. Remove the waxed paper and place the circle on a large baking sheet. Repeat with the rest of the dough. The crackers can touch as they do not spread during baking. Bake for 15 minutes at 350F, or until lightly golden but not brown. Cool on wire racks. Store in an airtight container. These big, thin, golden wafers are streaked with vegetable pieces. Makes 12 crackers.