Pikeperch with Rosemary and Celeriac Purée

Name: Pikeperch with Rosemary and Celeriac Purée
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Yield: 4
Ingredients: 4 pikeperch fillets; 50 ml olive oil; 1 sprig rosemary; 100 ml white wine; 100 ml stock; 2 tsp plain flour; 30 g butter; 800 g celeriac; 500 ml milk; 2 tbsp olive oil; salt, as needed; pepper, as needed; orange zest, as needed