For the Pesto: add all ingredients, except the olive oil to a food processor and pulse until everything is chopped, then slowly add in the olive oil until well combined.
Save pesto in an air tight container and use on salads, toast or pasta in the next couple of days.
add butter to a pan, over medium low heat and add in the bread. Lightly toast on one side of the bread, remove from heat and on the toasted sides layer your ingredients.
On both slides spread 1 tbsp pesto, then cheese.
Add more butter to the pan and add the slices of bread over medium low heat. Cover with a lid and let the cheese start to melt, about 1-2 minutes. Then layer the avocado and spinach on one side and then top with the other piece of bread and press down with a spatula, after 30 seconds to a minute, flip.