For the Blackberry Jam: In a small sauce pot add the blackberries, spices, vinegar, sugar and water.
Simmer on medium low for 10 minutes and stir frequently.
In a small bowl mix the cornstarch and 3 tablespoons of water to create a slurry.
Add mixture to jam mixture and stir on low heat. Let it simmer for 2-3 minutes until jam is thickened. Refrigerate jam in air tight container.
Assembly:
Spread one teaspoon of mayonnaise on one side of each slice of bread. With the mayo side down spread one tablespoon of jam on each slice of bread.Layer the cheeses on one slice of the bread and the other slice on top to create a sandwich.
On a skillet over medium heat, add your sandwich. Let it brown for 2 minutes and flip with a spatula. Lower heat if the cheese needs more time to melt.
Sprinkle salt on grilled cheese and cut on a bias. Serve warm.
Notes:
- If you've never used mayonnaise instead of butter to toast your grilled cheese, just do it. Trust me.
- This sandwich would also be delicious with sliced turkey or ham.