Preheat oven to 300 degrees. Butter a 9” x 13” baking dish. In a heavy 4-quart pan, combine cream, sugar, vanilla and salt. Warm over medium-low heat, just until steam comes off surface. Do not boil. Remove from heat, pour over cut-up croissants and let stand for 30 minutes
In a large bowl, whisk together egg yolks and eggs. Gently stir in croissant mixture. Fold in peaches and blackberries. Pour into baking dish and bake for 1 1/2 hours or until a knife inserted in center comes out clean. Cool slightly.
To serve: Cut into 12 squares, place one on each dessert plate, and serve with ice cream.