Grease a baking dish, fill with sliced croissants and mixed berries. Set aside.
Add cream cheese to mixing bowl and beat with hand mixer until smooth.
Add milk, sugar, eggs, vanilla extract and lemon zest and mix until it’s combined.
Pour cream cheese mixture over croissants and berries.
Cover and refrigerate overnight.
The next day, remove baking dish from refrigerator and bake covered with aluminum foil for 30 min at 350 degrees
Remove foil and bake uncovered for 10- 15 more minutes so the top gets golden brown and you can insert a fork until it comes out clean.
While casserole is baking, make your Vanilla Glaze!
Add powdered sugar, heavy cream or milk and vanilla extract to a small mixing bowl and whisk to combine until smooth and pourable.
Drizzle glaze over casserole after it's finished baking.
Serve warm and dust with powdered sugar - not necessary but it makes it even more appetizing!