1: Bring a saucepan of water to the boil. Once bubbling, gently lower in the egg and cook for 8 minutes. Once cooked, drain off the hot water and run it under a cold tap to cool, then peel the shell off the egg and grate it using the fine side of a box grater. 

2: Peel and roughly chop the onion, then heat the vegetable oil in a large frying pan over a medium heat. Once hot, add the onion and cook for a few minutes until softened. Roughly chop the mushrooms and add these to the pan to cook for a couple more minutes, stirring, until softened. 

3: Roughly chop the spinach and add this to the pan to warm through, then transfer it all into a bowl and stir in the grated egg and cheese. 

4: Put spread on all 4 slices of bread and pop the frying pan back on the heat. Place 2 slices of bread, spread side down, into the pan.

5: Spoon the mixture onto the 2 slices of bread in the pan, spreading it evenly to the edge of the bread, then place the remaining 2 slices on top, spread side up.

6: Cook gently for 4-5 minutes on one side, then turn the toastie over carefully and cook for a further 4-5 minutes on the second side, until lightly golden brown. The bread will be crisp and the cheese oozing. Pop the toasties on plates, slice in  half and tuck in.