Prepare the Bread: Cut the brioche or challah into small cubes and set aside. If your bread is fresh, you can dry it out in the oven at 300°F for 10-15 minutes.

Make the Custard Base: In a large mixing bowl, whisk together the egg yolks, milk, sugar, vanilla extract, cinnamon, and salt until well combined. Add the bread cubes to the custard mixture, tossing gently to ensure all the bread is soaked in the custard. Let sit for 10-15 minutes to absorb.

Whip the Egg Whites: In a separate bowl, beat the egg whites until stiff peaks form. This is what will give your soufflé its signature lightness. Gently fold the whipped egg whites into the custard-soaked bread mixture, being careful not to deflate the egg whites.

Bake the Soufflé: Preheat your oven to 375°F. Grease a large soufflé dish or individual ramekins with butter and lightly dust with sugar. Pour the soufflé mixture into the dish(es), filling them about 3/4 full. Bake for 20-25 minutes (for a large soufflé) or 12-15 minutes (for individual ramekins) until the soufflé is puffed up and golden brown on top.

Make the Cardamom Cream: While the soufflé bakes, make the cardamom cream. In a small saucepan, heat the heavy cream, cardamom pods, and sugar over medium heat until it just begins to simmer. Remove from heat and let the cardamom steep in the cream for 10 minutes. Strain out the cardamom pods, then stir in the vanilla extract.

Serve: Once the soufflé is baked and golden, remove it from the oven and dust with powdered sugar. Serve immediately with a drizzle of warm cardamom cream and a scattering of fresh berries.