Heat a chargrill plate (or barbecue) over medium heat. Remove husks and silks from corn cobs; discard. Cook corn cobs, turning occasionally, for 10 minutes or until grill marks appear and corn is tender. Cool slightly. Using a sharp knife, cut kernels from cobs; you will need 2 cups kernels.

Place corn kernels in a medium bowl with flour. Finely chop 2 of the green onions; reserve 2 for serving. Add remaining chopped green onion to the bowl; season, then stir to combine. Whisk eggs and buttermilk; stir through corn mixture until well combined.

Heat half the extra oil in a large frying pan over medium heat. Working in batches, spoon four ¼-cup measures of corn mixture into pan and flatten slightly with a spatula; cook for 2 minutes on each side or until golden and cooked through. Drain on paper towel; keep warm. Repeat with remaining oil and corn mixture to make eight fritters in total.

If you'd like to make the roast tomatoes toppping: cut remaining green onions into 12cm lengths, leaving the root ends intact. Place in a small roasting dish with the truss tomatoes. Combine 2 tablespoons of the extra virgin olive oil, the balsamic vinegar and sugar in a small jug; season to taste. Pour over vegetables.

Roast vegetables in a pre-heated oven at 180 degrees for 12 minutes or until tomatoes are just softened.

Serve fritters with roasted vegetables and pan juices, topped with reserved strips of green onion if at home, or just make the fritters for lunchboxes!