Cook the bacon in a non-stick skillet over medium heat until crispy, about 6-8 minutes. Once done, place it on a paper towel to drain excess grease.
While the bacon is cooking, mash the blackberries in a small bowl using a fork until slightly chunky. Set aside.
Take 4 slices of bread and spread 1 tablespoon of softened butter on one side of each slice.
Place 2 slices of cheddar cheese on the unbuttered side of each bread slice, followed by 2 slices of bacon and a generous tablespoon of the mashed blackberries. Top each with another slice of cheddar cheese and a second slice of bread, buttered side up.
Wipe out the skillet and place it over medium heat. Carefully place the sandwiches into the skillet.
Cook the sandwiches for about 3-4 minutes on each side, or until the bread is golden brown and the cheese has melted. Use a spatula to press down lightly on the sandwiches for even grilling.
Once cooked, remove the sandwiches from the skillet and let them cool for a minute. If desired, drizzle with honey before slicing in half.
Serve the sandwiches warm and enjoy!