Beet Green Strata

Lightly grease an 8-inch square baking dish.
In the prepared baking dish, toss together bread, greens and half the cheese. Spread evenly.
In a large bowl, whisk together olive oil, lemon zest, mustard, salt, and pepper. Add eggs and milk and whisk again. Stir in oregano. Very slowly drizzle the mixture over the bread and evenly sprinkle the remaining cheese over top. Cover and refrigerate overnight.
When ready to bake, preheat oven to 350 degrees. Uncover the strata and bake until the custard is set and the edges are browned, about 45 to 55 minutes. Place on a wire rack and let cool for 30 minutes before serving.