1. In a non-stick skillet, heat enough olive oil to fry mushrooms with minimal stirring. Season with salt and pepper. Set aside.
2. Brush a 23 x 33 cm (9 x 13 in.) baking dish with butter. Add half the bread cubes, the spinach, mushrooms, and half the feta, and then top with remaining bread cubes.
3. Whisk eggs in a large bowl, add the milk, green onions, and mustard. Season with salt and pepper.
4. Pour into the baking dish and cover with remaining feta. Refrigerate for 4 hours.
5. Bring to room temperature at least an hour before baking.
6. Preheat oven to 180°C (350°F). Bake for 50 to 60 minutes, or until a knife inserted into the center of the dish comes out clean. If the top browns too quickly, cover with aluminum foil.
7. Serve stratta with a green salad on the side if you like.

Tip

• For more flavourful mushrooms, add a minced onion or two shallots, a chopped clove of garlic, and some salt when frying... or visit IGA.net to discover my recipe for oven-roasted mushroooms!
• Avoid stirring mushrooms when frying so they ’ll produce less liquid. This will result in tastier mushrooms with a nicer colour.