A perfect addition to brunch.
Butter a 9X11 casserole dish with 2 tablespoons of butter.
Heat oil in a large sauté pan and cook sausages according to package directions. Remove, let cool and chop into small pieces. In the same pan, add the onion and cook for approximately 3 minutes. Add the spinach a few handfuls at a time, cooking until wilted. Remove from pan and squeeze out some of the liquid. Mix together the spinach and sausage.
In a large bowl, whisk the eggs together with the half and half, salt, pepper and nutmeg.
Lay the bread cubes in the casserole dish. Layer evenly over the bread half the spinach mixture, half of both cheeses and half the egg mixture. Repeat with the remaining halves, making sure the bread is covered in the liquid.
Cover and refrigerate for a few hours or overnight. When ready to bake, remove from fridge and let rest at room temperature for 30 minutes.
Preheat oven to 325°F and bake the strata 50 to 60 minutes uncovered.