Soufflé60 gmbutter, plus extra for greasing20 gmfinely grated parmesan, plus extra for mould1golden shallot, finely chopped35 gmplain flour250 ml (1 cup) hot milk2 tspDijon mustard4egg yolks75 gmblue cheese, such as Saint Agur or Bleu d’Auvergne, coarsely crumbled5eggwhitesWalnut and celery salad1 clovegarlic, halved2 tspDijon mustard20 ml (1 tbsp) tarragon vinegar60 ml (¼ cup) walnut oil2stalks of celery, finely shaved lengthways and placed in iced water1celery heart, finely shaved70 gmwalnut halves, toasted
Butter a deep-sided 1 litre-capacity ovenproof ceramic dish and dust with finely grated parmesan, shaking to remove excess. Make a collar out of a double layer of buttered baking paper and tie around top of mould, buttered side inward, standing about 5cm high.
Preheat oven to 180C. Melt butter in a heavy-based saucepan, add shallot and cook for 2-3 minutes or until soft, add flour and stir continuously for 1-2 minutes. Gradually add milk, mixing until smooth, then bring to the boil, stirring continuously and cook for 2-3 minutes or until thick. Remove from heat, add parmesan, mustard and egg yolks and mix to combine. Season to taste with sea salt and freshly ground white pepper, set aside for 5 minutes, then stir in blue cheese, taking care not to break up chunks.
Whisk eggwhites and a pinch of salt until soft peaks form. Fold one third of the eggwhites into cheese mixture to lighten, then fold through remaining eggwhites. Pour into prepared dish and bake for 30-35 minutes or until puffed and golden.
Meanwhile, for walnut and celery salad, rub cut side of a garlic clove around bowl, add mustard, vinegar and walnut oil, season to taste and whisk to combine. Drain celery, add to bowl with celery heart and walnut halves and toss to coat. Remove collar from soufflé and serve immediately with salad.