Spread both side of the bread with the goat cheese, using any amount that you prefer.
Layer one side of the bread with the slice of cheddar cheese and with the slices of Gruyère cheese. (I couldn't find Gruyère in slices, so I bought a chunk of these cheese) 4–5 slices off of a cheese chunk is about equivalent to a slice).
Add the olive oil to a fry pan that has been warmed over medium-heat. I put the pat of butter in the pan and with a knife guide it to melt around the size of the bread slice.
Add the sandwich and cook over medium heat around 4 minutes until the bread is golden brown. Lift the sandwich, with a spatula and melt another pat of butter and flip the other side into the pan. After about 4 minutes, the second side should be beautifully toasted and the cheese should be melted. Be sure to keep your eye on the sandwich, as you don't want it to burn. It can go from golden brown to burnt quickly.