We first used this on grilled ham and fontina cheese sandwiches, but it was also great with poultry and pork chops/loin/tenderloin.

1 cup fresh blackberries
1/8 cup finely diced sweet onion or shallot
1/4 cup Dijon mustard (recipe below if you want to make your own or use purchased)
1-1/2 Tbsp sugar
1 tsp honey
1 tsp chopped fresh rosemary
pinch of cayenne pepper
1 tsp balsamic vinegar
1 tsp cornstarch
4 oz Mason jars
Mix blackberries, onion, Dijon mustard, sugar, honey, rosemary, and cayenne in a small saucepan. Over medium heat, stir and mash blackberries with the back of a spoon until mixture comes to a boil.
In a small bowl, combine vinegar and cornstarch. Add to blackberry mixture. Stir to combine and let simmer until mixture thickens slightly, about 30 seconds to a minute. Remove from heat.
Store in refrigerator for up to a month or water bath can for 10 minutes, cool, making sure lids "pop" and seal, then store in a cool dry place (with rings loosened slightly) for up to 6 months.
Dijon mustard
2 Tbsp brown mustard seeds
2 Tbsp yellow mustard seeds
1/4 cup dry white wine
1/4 cup white wine or sherry vinegar
1/4 tsp Kosher salt
1-2 tsp honey (you can stir in more later on to taste if needed)
Mix the mustard seeds, wine, vinegar and honey in a glass bowl. Glass is used because the acid in the wine and vinegar can react with some metals and produce an odd taste. Cover with plastic wrap and let sit for 2 days at room temperature. Transfer mixture to a blender or small food processor, add in salt and 1 tsp honey, then process until desired consistency. If you want a completely smooth mustard, process as much as you can, then put mixture through a fine mesh strainer. Place in a glass container and refrigerate for 2-3 days before using.
Store and preserve as above.

1 cup fresh blackberries
1/8 cup finely diced sweet onion or shallot
1/4 cup Dijon mustard (recipe below if you want to make your own or use purchased)
1-1/2 Tbsp sugar
1 tsp honey
1 tsp chopped fresh rosemary
pinch of cayenne pepper
1 tsp balsamic vinegar
1 tsp cornstarch
4 oz Mason jars
Mix blackberries, onion, Dijon mustard, sugar, honey, rosemary, and cayenne in a small saucepan. Over medium heat, stir and mash blackberries with the back of a spoon until mixture comes to a boil.
In a small bowl, combine vinegar and cornstarch. Add to blackberry mixture. Stir to combine and let simmer until mixture thickens slightly, about 30 seconds to a minute. Remove from heat.
Store in refrigerator for up to a month or water bath can for 10 minutes, cool, making sure lids "pop" and seal, then store in a cool dry place (with rings loosened slightly) for up to 6 months.
Dijon mustard
2 Tbsp brown mustard seeds
2 Tbsp yellow mustard seeds
1/4 cup dry white wine
1/4 cup white wine or sherry vinegar
1/4 tsp Kosher salt
1-2 tsp honey (you can stir in more later on to taste if needed)
Mix the mustard seeds, wine, vinegar and honey in a glass bowl. Glass is used because the acid in the wine and vinegar can react with some metals and produce an odd taste. Cover with plastic wrap and let sit for 2 days at room temperature. Transfer mixture to a blender or small food processor, add in salt and 1 tsp honey, then process until desired consistency. If you want a completely smooth mustard, process as much as you can, then put mixture through a fine mesh strainer. Place in a glass container and refrigerate for 2-3 days before using.
Store and preserve as above.