Preheat oven to 180°C / 350°F. Butter a 9×13 baking dish.
In a pan, melt butter and sauté mushrooms, onion, herbs, salt, pepper, and garlic powder until golden and fragrant. Set aside.
2 tbsp butter, 1½–2 cups sliced mushrooms, ½ cup diced yellow onion, 1–2 tbsp fresh sage and thyme
In a bowl, whisk together eggs, milk, Simply Desserts Vanilla Pudding mix, salt, pepper, and Gruyère cheese.
2 tbsp Simply Desserts Vanilla Pudding, 5–6 eggs, Salt, 2 cups grated Gruyère cheese, 2 cups whole milk or half-and-half
Layer bread chunks and sautéed vegetables in the baking dish. Pour the egg mixture evenly over the top.
1 loaf brioche or sourdough bread
Finish with a generous layer of grated Parmesan cheese.
Parmesan cheese
Bake for 45 minutes, or until golden, set, and bubbling.
Let rest for 10 minutes before slicing and serving.