Preheat your oven to 350°F (175°C).

Cut your brioche into 1-inch cubes and place them in a large bowl.

In a medium bowl, whisk together the eggs, half and half, vanilla extract, cinnamon, nutmeg, lemon juice, and salt until smooth and creamy.

Slice your fresh peaches and toss them gently with the brioche cubes in the large bowl.

Pour the custard mixture over the brioche and peaches, folding everything together.

Spread the soaked bread and peach mixture evenly in a greased baking dish.

Mix together the flour, brown sugar, and cinnamon for the crumble topping, then cut in the chilled butter until resembling coarse crumbs.

Evenly sprinkle the crumble topping over the bread mixture in the baking dish.

Bake for 45-60 minutes until the top is golden brown.

Let it rest for about 10 minutes before dusting with powdered sugar and serving.