01 -
In a 2-quart saucepan, toss together the tied thyme, sugar, blueberries, and lemon juice. Let it come to a rolling boil on medium-high heat, then lower the flame and simmer lightly for 10 minutes. Turn the heat even lower and cook for another 10 minutes until it’s thickened up. Take the thyme out and let it cool down.
02 -
Spread the blueberry jam (once it’s cooled) on half of the bread slices. Add a blend of the mozzarella and cheddar cheeses on top of the jam, then press another bread slice on top to close.
03 -
Warm 2 tablespoons of butter in a cast iron skillet over medium heat. Place two sandwiches in the pan, cover them, and cook for 2 to 3 minutes on each side until the bread is golden and the cheese melts. If the bread starts browning too fast, lower the heat.
04 -
Do the same for the rest of the sandwiches using the butter left in the skillet.
05 -
Slice the sandwiches in half. Sprinkle some flaky sea salt on top, and if you like, add a few leaves of fresh lemon thyme before serving.