Press the tofu for at least 20 minutes to remove excess moisture, then cut into bite-sized cubes.
In a bowl, toss the tofu with cornflour until evenly coated.
Heat the vegetable oil in a large non-stick frying pan or wok over medium-high heat. Add the tofu and cook until golden and crisp on all sides, turning occasionally. Transfer to a plate.
In the same pan, add a splash more oil if needed, then stir-fry the garlic, ginger, and red chilli for 1–2 minutes until fragrant.
Add the chopped bell peppers and mangetout. Stir-fry for 2–3 minutes until tender-crisp.
In a small bowl, whisk together soy sauce, hoisin sauce, rice vinegar, maple syrup, and a splash of water.
Return the tofu to the pan, pour in the sauce, and toss everything to coat. Let it bubble for a minute until the sauce thickens slightly.
Sprinkle over the sesame seeds and spring onions, then serve hot with rice or noodles.