Cut the croissants into quarters. Add to a to an 8x8 pan, press firmly into the pan.
In a mixing bowl add the eggs, half and half, beer, both sugars, vanilla, and salt, whisk until well combined.
Pour the mixture over the croissants, sprinkle with pecans. Cover and refrigerate overnight and up to 3 days.
Preheat the oven to 375°F.
Remove the casserole from the fridge while the oven preheats.
Bake uncovered for 45 minutes or until the center has puffed and top is slightly crisp.
Remove from oven, allow to cool slightly, cut into 9 squares.
In a bowl, add the mascarpone and whip with a hand mixer until creamy. Add the heavy cream, beat to combine. Then beat in the orange juice and vanilla, then the powdered sugar.
Serve the casserole with mascarpone cream.