Heat oven to 190C/170C fan/gas 5. To make the candied walnuts, shake the walnut halves in 2 tbsp water, then toss in the sugar. Scatter over a baking sheet and bake in the oven for 6-8 mins until golden brown. Remove from the oven and allow to cool.
Carefully peel the rind off the Brie and discard. Put the gooey inside in a medium-sized bowl. Using a spoon or small whisk, whip the Brie until pale and spoonable. To make the dressing, whisk the oil and vinegar together, then season.
In a large bowl, combine the walnuts, dates and rocket, then mix with some of the dressing. Place a spoonful of whipped Brie in the middle of each serving plate and arrange the salad around it. Scatter over the croutons, drizzle with a little extra dressing and serve.