Soufflé mac ’n’ cheese

Name: Soufflé mac ’n’ cheese
Prep time: 30 min
Cook time: 40 min
Total time: 1 h 10 min
Cuisine: European, American, Mediterranean
Ingredients: 25g butter; 1 tbsp olive oil; 200g shallots , sliced; 2 garlic cloves , crushed; 500g pasta tubes; 2 tbsp flour; 500ml whole milk; 140g gruyère , grated; 4 eggs , separated; 1 tbsp Dijon mustard; 1 tsp grated nutmeg; 180g pack cooked pulled ham hock; 100g mature cheddar , chopped into chunks; 3 tbsp cider vinegar; 100ml sunflower oil; 1 tbsp snipped chives; 1 tbsp chopped tarragon; 1 round lettuce , shredded; 2 Little Gem lettuces