Drizzle the tomato slices with a little of the olive oil and the balsamic vinegar, then grill until lightly softened and beginning to caramelise.
Heat the remaining olive oil in a frying pan over a medium heat. Add the shredded tempeh and stir-fry for 2–3 minutes. Pour in the soy sauce and continue cooking for another minute until the tempeh is lightly browned.
Halve the avocado, remove the stone and slice the flesh. Drizzle with a little lemon juice to prevent it from browning.
Toast the sourdough, if you prefer.
Arrange the avocado slices over the sourdough, then top with the grilled tomatoes. Season with freshly ground black pepper and drizzle with a little extra balsamic vinegar if desired.
Spoon the warm tempeh over the top and serve with a handful of fresh rocket.