Recipe: Gill Meller's Baked Mushrooms with Celeriac and Lentils

Ingredients

• 3 tbsp extra-virgin olive oil, plus extra for baking
• 1 onion, halved and thinly sliced
• ½ celeriac, peeled and cut into 2cm (¾in) dice
• 2 garlic cloves, thinly sliced
• 1 small handful of marjoram
• 8 large Portobello mushrooms, stalks removed but reserved
• 200ml (7floz) vegetable stock
• 75g (2½oz) puy lentils, rinsed
• 1 tsp Dijon mustard
• 2 tsp cider vinegar
• 1 handful of coarse breadcrumbs
• Sea salt and freshly ground black pepper