I think plums and cardamom are an amazing fruit and spice combination. I make cakes and crumbles with them in the late summer/early fall, when plums are in season here. I decided to use my homemade plum jam for this, since store-bought plums aren't very nice at this time of year. You could substitute another jam or tart fruit puree, as long as it is smooth and not too sweet.
Stockout tested this recipe, and sent me extensive feedback, so I have edited the instructions below to ensure that they are clear. —MaryMaryCulinary
Preheat oven to 350. Butter 4-1 cup ramekins and sprinkle with sugar to coat inside. Set aside. You can use any size ramekins, adjusting the baking time as necessary.
Beat egg whites in a large bowl with a pinch of salt until soft peaks form. Add 3 tablespoons of the sugar, beating until stiff peaks form.
Beat egg yolks with remaining sugar on high speed, until thick and light. Beat in jam, lemon juice and cardamom.
Fold about 1/4 of the beaten egg whites into the yolk mixture with a spatula or whisk to lighten. Add the remaining whites and fold in gently but quickly. It is better to leave a few white streaks than to over fold.
Fill ramekins to top and level off with a straight edge. Run the tip of your finger around the inside edge to clean it. Put in the oven for 14-18 minutes*. I use a sheet pan so I can remove them quickly and get them on the table. Souffles will rise at least an inch over the top of the dish and be golden when ready. Bake for the shorter time if you like a creamy centre, or for the longer time if you like them a bit drier. At the 14-minute mark, you can quickly open the oven door and touch the top to test. Remove, sprinkle with powdered sugar and serve immediately.* I use glass ramekins, but ceramic may take longer. Stockout found that ceramic 1-cup ramekins needed 8-10 minutes longer to bake.
These can also be baked an hour before dinner and rebaked for 10 minutes just before serving. They will rise again. Thanks for that tip, Stockout!