Preheat the oven to 200 degrees Celsius (FAN), 425 Fahrenheit FAN, gas 7, or static oven 220 degrees Celsius.
Prepare the potatoes
Wash and boil the potatoes until they are 75% done; once done, drain them and set them aside.
Prepare the cod
Prepare the panko parmesan crust by mixing together the thinly chopped garlic, dry parsley, black pepper, salt to taste, the breadcrumbs and the grated Parmesan cheese.
Pat dry the fish fillets and put them in the centre of the baking tray which has been lined with some parchment paper.
Top the cod fillets with the panko parmesan mixture without pressing it, as you'll want the steam to escape while cooking, so that the crust doesn't get soggy.
Drizzle the lemon juice and olive oil on the fillets.
Prepare the green beans
Wash and trim the green beans and put them in a large bowl; dress the green beans with the olive oil, salt and pepper to taste, and the thinly chopped garlic, and mix well.
Place the green beans and potatoes on the same baking tray as the cod.
Bake the one-sheet meal
In the preheated oven, place the baking tray in the center and bake for 12-14 minutes, until the fish is fully cooked and the crunchy crust is golden brown.
Should the potatoes be small, these can be boiled whole, but if they are large, cut them in half, as they will need to be nearly fully boiled before baking in the oven, as the cod has a very short cooking time.If you like your green beans more on the soft side, you can simmer them in boiling water for about 3 minutes before seasoning them and baking them.