Cook the eggs in boiling water for 8-10 minutes. Cool slightly under cold water, then peel and leave to cool
Meanwhile, wash the broccoli and divide into florets. Peel the thick stems and cut into small pieces. Cut the tomatoes into strips.
Cook the broccoli in boiling salted water, covered, for 5-7 minutes over a medium heat. Add the tomato strips and cook for 3 minutes. Drain well.
Meanwhile, toast the pine nuts in a dry pan until pale golden. Allow to cool.
Mix the yogurt with salt, pepper, mustard and oil. Peel the garlic and crush into the dressing.
Clean the button mushrooms and cut into slices.
Mix the mushrooms, tomatoes and broccoli into the yogurt dressing and leave to stand for 10 minutes.
Meanwhile, cut the eggs into wedges and add to the salad. Garnish with toasted pine nuts.