To a blender add half the dill, all of the chives, parsley, cucumber, garlic clove, yogurt, olive oil, tahini, salt, and pepper. Squeeze in the juice from the lemon. Blend until the mixture is creamy and smooth. Refrigerate until ready to serve.

Prep the sandwich: Heat a nonstick pan on medium heat. Once hot, add half of the butter. Brown the ham slices on both sides then remove from the pan.

Spread the mayo on one side of each bread slice.

Layer the bread with cheese, ham, cheese, and top with a bread slice. Spread the remaining butter on both of the outer sides of the sandwich.

Grill sandwich: Lower the heat in the pan to medium low. Cook the sandwich to golden brown on both sides and until the cheese has melted completely, covered with a lid.