For the salad: Preheat your oven to 350 degrees F (180 degrees C/Gas mark 4).
Arrange the butternut squash and shallots on a baking sheet, drizzle with the olive oil and balsamic vinegar and mix together. Sprinkle over a pinch of sea salt and a pinch of black pepper.
Bake until the squash and shallots are lightly browned and tender, about 35 minutes, checking halfway through to give them a mix around.
Meanwhile, in a heavy-bottomed skillet (no need to add oil), toast the pecans and pumpkin seeds over medium heat until fragrant, 1 to 2 minutes. Tip the nuts into a bowl and set aside.
For the dressing: Whisk the oil, vinegar, mustard, lemon juice and a pinch of sea salt in a cup or jar.
Lay the mixed salad leaves and radicchio wedges on a large serving board or platter. Arrange the roasted shallots and squash on top. Drizzle over the dressing. Then sprinkle over the toasted pecans and pumpkin seeds and crispy fried onions.