Place a medium sized saucepan over high heat. Add 1 Tbsp of oil
Add the eggs, swirling to cover the base of the pan, making an omelette.
Continue to cook until golden. Flip over and cook through. Remove from the pan and place on a plate or board to cool.
Place the pan back on the heat and cook the steak as you like it. Remove from the heat and set aside to cool.
Clean the sauce pan and place back over the heat. Saute the mushrooms in a little
oil. Transfer to a small container to cool.
Sauté the spinach until just wilted, then set aside to cool.
Clean the saucepan, and return to the heat, with the last drizzle of oil.
Add the cherry tomatoes and lightly sauté to release juices. Season well with salt and pepper.
Drizzle with balsamic glaze and add the chopped herbs.
Remove from the pan and set aside to cool.
Using a sharp knife, cut a hole in the top of the bread. This will form the lid for the sandwich. Trim it underneath so it can be used to enclose the sandwich once it is filled. Hollow out the bread, leaving a cavity for the filling ingredients. Reserve the filling to make breadcrumbs for something else
Spread some mayonnaise inside on the bottom of the bread.
Layer in the prosciutto, followed by the steak, sliced as necessary to fill the sandwich. Spread over the pesto.
Follow with the mushrooms, gorgonzola, then the tomatoes.
Next, place over the omelette, trimming as necessary to fit. Top with the asparagus.
Spread over the onion marmalade. It doesn’t really matter what order you put everything in but just think about the different colours and how they will look when the sandwich is cut.
Plug the top with the reserved piece of bread.
Wrap the whole bread tightly, over and over with cling film and place in the fridge to chill and set for 3 to 4 hours or overnight if preferred.
To serve, remove the cling film and slice into wedges.