1 Scrub potatoes and place in a pot with enough water to cover. Cover pot and cook until potatoes are knife-tender, about 20 minutes.
2 Peel the kohlrabi, coarsely grate, season with salt and let stand about 10 minutes to allow the water to drain out.
3 Meanwhile, rinse scallions, shake dry and cut diagonally into thin rings.
4 Rinse and dry tomatoes and cut into quarters. In a small bowl, season balsamic vinegar with salt and pepper, then toss with the tomatoes and scallions.
5 Drain the potatoes, rinse with cold water, peel and press through a ricer into a bowl.
6 Drain kohlrabi in sieve. Add kohlrabi, oats and egg to the potatoes, mix to combine and season with salt and pepper.
7 Rinse chives, shake dry and cut into 5 cm (approximately 1/4-inch) pieces.
8 Heat 1 teaspoon oil in a non-stick pan. Divide half of the potato mixture into 4 portions and add to pan, flattening into fritters with the back of a tablespoon.
9 Cook the fritters with half the chives over low heat for about 3 minutes on each side. Remove from pan. Repeat with remaining oil, potato mixture and chives.
10 Rinse basil, shake dry and pluck the leaves. Add to tomato salad and season with salt and pepper. Serve fritters with the salad.