Heat oven to 500 degrees. Spread croissants on a large baking
sheet and toast, cut side up, until golden brown, 5 to 10 minutes
(watch carefully to see that they do not burn). Let cool, then tear
into large bite- size pieces.
In a medium skillet over medium-high heat, warm the olive oil. Add
sliced scallions and sausage meat; cook, breaking up meat with a
fork, until mixture is well browned, about 5 minutes. Stir in sage,
and remove from heat.
In a large bowl, toss together croissants and sausage mixture. In a
separate bowl, whisk together eggs, milk, cream, 1 1/2 cups
cheese, salt and pepper.
Lightly oil a 9- x 13-inch baking dish. Turn croissant mixture into
pan, spreading it out evenly over the bottom. Pour custard into
pan, pressing croissants down gently to help absorb the liquid.
Cover pan with plastic wrap and refrigerate at least 4 hours or
When ready to bake the casserole, heat oven to 350 degrees.
Scatter the remaining grated cheese over the top of the casserole.
Transfer to oven and bake until casserole is golden brown and firm
to the touch, 45 minutes. Let stand 10 minutes. Garnish with
sliced scallion tops before serving.