Take the first topside slice of beef and put it onto a working surface. Cut one slice of cooked ham in two halves (I prefer using wide slices of cooked ham because I can cut them in different shapes and sizes according to my needs).
Put one of the cooked ham slices you cut onto the topside slice as shown in the photograph.
On the top of the ham put one slice of cheese.
Slices of processed cheese melt easily so, to limit the cheese from coming out during the cooking, we need to flip the topside slices edges towards the inside as shown in the photograph.
Next, roll the topside slice up.
Tie the roll with a piece of string; this will keep the roll together during the cooking. There you are, the first involtino is ready! (involtino is the singular word and involtini is the plural).
Repeat the procedure until you have 8 involtini.
Coat each involtino with flour.
Now, they are ready for cooking.
Take a sauté pan that can contain all the involtini, put the olive oil into it and heat the oil (medium/high heat). Also, keep a small pan with the beef stock handy because you will need a ladleful of stock soon.
When the oil is hot, add all the involtini into the pan.
Brown the involtini. This will take few minutes, usually a couple of minutes for each side.
Use a wooden spatula so that you can easily turn the involtini around until they are browned.
Once browned, you will also notice that the bottom of the pan starts becoming a bit too dry so this is the right time to add the white wine.
Let the wine evaporate for a couple of minutes, bring the heat down to medium/low and add the sage leaves.
Season with black pepper.
Season with salt.
Add just one ladleful of beef stock and cook for few minutes until the sauce thickens (usually no more than 8-10 minutes).
They are ready!
Serve them hot, accompanied with mashed potatoes.