In a medium saucepan, heat oil over medium heat. Add shallot and garlic; cook until fragrant, approximately 2 minutes. Add plums, dates, ginger, orange juice, and ¼ cup water. Bring mixture to a boil over medium heat. Reduce heat to low, and simmer for 10 minutes. Add pectin, brown sugar, mustard, cardamom, and vinegar, stirring constantly until combined, approximately 2 minutes. Transfer plum chutney to a medium heatproof bowl. Let cool completely.
Using a serrated bread knife in a gentle sawing motion, cut croissants in half horizontally. Spread a thin layer of plum chutney on cut sides of croissants. On bottom halves of croissants, layer lettuce and turkey. Cover with remaining croissant halves. Serve immediately.
Notes
*We used Original Sure-Jell Premium Fruit Pectin.
Make-Ahead Tip: Plum chutney can be made day in advance, stored in an airtight container, and refrigerated.
Recipe by TeaTime Magazine at https://teatimemagazine.com/turkey-tea-sandwiches-2/