Prepare the basil mayonnaise by combining basil paste and mayonnaise in a bowl.

Stir the mixture until well combined.

Cover the basil mayonnaise and refrigerate until needed.

Spread 1 teaspoon of basil mayonnaise evenly on one side of each slice of bread.

On one slice of bread, layer 1 slice of provolone cheese.

Add the tomato slices on top of the provolone.

Arrange 3 slices of avocado over the tomatoes.

Place 3 strips of cooked bacon on top of the avocado.

Layer 4 slices of thickly cut turkey over the bacon.

Top with the other slice of bread, basil mayonnaise side down.

Spread 1/2 tablespoon of softened butter on the top and bottom of the sandwich.

Grill the sandwich on a grill or in a panini press.

Grill until the bread is golden brown and the cheese is melted.