Line a 3-1/2- or 4-quart slow cooker with a disposable slow cooker liner. Place bread cubes in prepared slow cooker. In a large bowl beat together cream cheese and lemon curd with a wooden spoon until smooth. Whisk in milk, sugar, eggs, poppy seeds, almond extract, and salt. Pour mixture over bread cubes in cooker. Cover and chill for 4 to 24 hours.
Cover and cook on low-heat setting for 7 to 8 hours or until a knife inserted near the center comes out clean. Turn off cooker. Let stand for 30 minutes. Carefully lift liner from cooker, using a plate to transfer French toast to a cutting board. Slice French toast to serve. If desired, sprinkle with powdered sugar and serve with fresh berries.