Combine blueberries and cream cheese in the bowl of a mixer and mix with paddle for about two minutes until the cream cheese takes on a pale purple hue. Use a spatula to transfer to a container and store in fridge. 

In a frying pan add olive oil, and once hot add slices of prosciutto and fry over medium heat, flipping after several minutes, until crisp. Remove prosciutto with tongs and transfer to paper towel.

Between two slices of sourdough bread, spread two tbsp of blueberry cream cheese, layer with prosciutto, and follow with the shredded cheddar. Place in the hot pan with the remaining oil from the prosciutto. Cook 2-3 minutes over medium-high heat until the bottom is golden brown, flip and cook another 2-3 minutes, then remove from heat.