Make the Blackberry Jam:

In a small pot over low-medium heat, add blackberries, sugar, and lemon juice. Use a potato masher to gently burst all the berries until a thin sauce forms.

Turn the heat to medium-high and allow the sauce to bubble and reduce until thickened, stirring frequently. The sauce will continue to thicken as it cools.

Assemble the Sandwiches:

Butter one side of each slice of bread. In a large pan with the heat off, place two slices of bread butter-side-down. Spread 1 heaped tablespoon of the blackberry jam on each slice, top with 3 wedges of Brie, 2 slices of bacon, and a pinch of chili flakes if using. Add another slice of bread on top (buttered side facing out).

Cook the Grilled Cheese:

Turn the heat to medium and fry the sandwiches until golden brown on both sides, with the Brie starting to melt and ooze out. Repeat with the remaining sandwiches if necessary.

Serve:

Slice the grilled cheese sandwiches in half and enjoy while warm.