Grease a 9x13-inch baking dish. Spread half the cubed bread in the dish. Scatter half the raspberries and sliced almonds on top. Repeat with remaining bread, berries, and almonds.
Make the custard: Whisk together eggs, milk, yogurt, maple syrup, vanilla, almond extract, lemon zest, and salt (plus lemon juice if using).
Pour custard evenly over the bread and berries. Press down slightly to soak.
Cover and refrigerate overnight. Let the bread soak up all that lemony goodness.
In the morning, preheat oven to 350°F (175°C). Mix 2 tbsp sugar with a bit of lemon zest and sprinkle it over the top, along with a few extra sliced almonds.
Bake uncovered for 40–45 minutes, until puffed, golden, and set in the center.
Let cool slightly, then dust with powdered sugar or drizzle with lemon glaze just before serving.