Grill or toast the bread slices until golden brown. Drizzle with a small amount of the olive oil and set aside.
Bring a small saucepan of salted water to a boil. Add the fava beans and cook until tender, 1 to 2 minutes. Drain well. Peel and put in a bowl. Add the fava blossoms, stone fruit blossoms and spring onion. Set aside.
In a blender combine the orange juice, lemon juice, shallot, mustard and thyme. Blend on medium speed. With the blender running, slowly add the olive oil until completely incorporated. (It is best to do this just before serving.) Season to taste with salt and pepper.
Pour a small amount of the vinaigrette over the fava mixture and toss gently. Taste and adjust the vinaigrette and salt and pepper as needed. Arrange in small mounds of the spring salad in the center of six plates. Place a crouton on each plate and serve.