Slice the bread into 1" thick slices, then cut each piece of bread into quarters. Fit the chunks of bread into a deep 9x13 baking dish, you want to pack them in fairly tightly next to each other, a couple layers deep. Layer the peaches on top of the chunks of bread. Lightly beat the eggs. Add the milk, cream, sugar, cinnamon, vanilla, and salt to the bowl with the eggs and whisk to combine. Carefully pour the cream mixture over the bread and peaches in the baking dish. Cover tightly with foil and refrigerate overnight.
Preheat the oven to 350 degrees. Place the cold casserole in the oven and bake for 20 minutes. While the casserole is baking, stir together the brown sugar, butter and pecans for the topping. Remove the casserole from the oven, uncover, and drizzle with the pecan topping. Bake an additional 30 minutes, uncovered. Remove from the oven and let rest 10 minutes before serving. Enjoy!