In a small bowl, mix together the soy sauce, maple syrup, cider vinegar, water, miso or mustard, garlic, ginger and, if using, the red pepper flakes.

Whisk until you get a smooth sauce. Set aside.

Cut the tofu into cubes. Pat them dry carefully with paper towel.

In a bowl, toss the tofu cubes with the cornstarch, a small pinch of salt and a little black pepper until they are lightly coated.

In a large pan, toast the walnuts or hazelnuts dry over medium heat for 3 to 4 minutes, stirring often, until they are lightly golden and fragrant. Transfer to a small bowl and set aside.

In the same pan, add 1 tablespoon of oil and heat over medium heat.

Add the sliced shallots and cook for 3 to 4 minutes, until they become soft and translucent.

Add the second tablespoon of oil and the tofu cubes. Cook for 3 to 5 minutes, turning them regularly, until they are nicely golden on several sides.

Add the prunes to the pan and cook for 1 to 2 minutes so they start to soften and lightly caramelise with the tofu.

Pour the sweet and savoury sauce into the pan. Mix gently to coat the tofu, prunes and shallots. Let cook over medium heat for 3 to 5 minutes, until the sauce reduces and thickens slightly and nicely coats the ingredients.

Add the toasted nuts to the pan and mix briefly off the heat.

Taste and adjust seasoning with salt, pepper or a little more red pepper flakes if needed.

Serve immediately over rice, quinoa or soba noodles. If you like, you can finish with a little chopped chives or parsley on top.