Tuna mornay

Name: Tuna mornay
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: American
Ingredients: 40 g unsalted butter, plus extra for greasing; 300 g penne pasta; boiling water, for soaking; 200 g tasty cheese, cut into pieces; 6 sprigs fresh flat-leaf parsley, leaves only; 60 g panko breadcrumbs; 1 brown onion, cut into halves; 2 garlic cloves; 2 tbsp plain flour; 350 g milk; 425 g canned tuna, drained; 410 g canned sweet corn kernels, drained (approx. 250 g after draining); 410 g canned creamed corn; ¼ tsp paprika; ½ tsp salt, to taste, plus extra to season; ¼ tsp ground black pepper, to taste, plus extra to season; 1 tbsp lemon juice (optional)