Preheat oven to 375°F. Spray a 12-cup muffin pan with nonstick cooking spray.
Slice baguette into 12 ¾"-wide slices and place a slice in the bottom of each muffin cup. (You will not use all of the bread loaf.)
In a medium bowl, whisk eggs, milk, sugar, vanilla extract, maple syrup, nutmeg, and salt together.
Pour over bread slices, dividing evenly between all muffin cups. Let it soak in while you prepare topping. As the bread softens, it will be easier to push the bread more securely into the bottom of the cup. Note: Do not overfill the muffin cups. Let some soak into the bread then add a little more to the bottom.
In a medium bowl, add apples and sprinkle with lemon juice. Add sugar, cinnamon, maple syrup, and melted butter to the bowl. Stir well.
Using a ¼ cup measuring cup, top each of the pieces of French bread with some apple mixture. Use all of the mixture.
Place in a preheated oven and bake for 25-30 minutes or until the egg mixture has set.
Remove and place muffin pan on a wire rack to cool.
Once cool, push any apple mixture that has toppled off back onto the muffins. They should be setting lower in the muffin cups. Run a knife around the outside edge of each muffin then remove carefully. I like to lift mine out gently with a fork.
Let them cool completely then sprinkle the tops with powdered sugar.
Serve warm with maple syrup on the side.
Notes
STORE/FREEZE/REHEATStore cooled muffins in an airtight container and refrigerate for up to 3 to 4 days.Freeze cooled muffins individually wrapped then in a freezer-safe bag for up to 3 months.Reheat in the microwave for about 30 seconds or until warmed through. If frozen, reheat for a minute or until heated through.