Step 1

Heat the olive oil and butter in an extra large ovenproof skillet over medium heat.

Step 2

Once heated, add the cabbage, onion, celery, garlic, sea salt and black pepper to the pan.

Step 3

Sauté until the vegetables are crisp tender - about 10 minutes.

Step 4

Mix in the dill, mustard powder, lemon zest, and lemon juice.

Step 5

Pour the heavy cream and 1 cup Parmesan cheese into the pan. Mix in and keep stirring until the cheese has melted and combined with the heavy cream.

Step 6

Reduce heat to medium low and let simmer to allow the sauce to thicken.

Step 7

Once the sauce has started to thicken, stir in the tuna and the peas.

Step 8

Sprinkle the remaining Parmesan over the top of the dish and transfer to the oven.

Step 9

Broil on high for 3-5 minutes or until the Parmesan on top has made a golden brown crust.