Line a baking sheet with parchment paper, set aside. Preheat oven to 240°C (464°F). Crack eggs in a medium bowl and beat until slightly fluffy. Add milk, whipping cream and maple syrup and whisk until incorporated.
Place slices of Stollen in a large rectangular baking dish or a few smaller pans / plates. Leave enough space around each slice, so you can flip it later. Pour in the egg mixture. Let Stollen soak for about 5 minutes, flip it once or twice during this time. Be careful because it’ll be very soft.
Place 1 piece of butter in a large non-stick pan and cook over medium-high heat. When it starts to foam, place in 4 slices (less if your pan is small) of Stollen and fry for 2-3 minutes. Flip them over, add another piece of butter and fry until golden brown.
Transfer slices to the prepared baking sheet and repeat with the second batch. Once the whole Stollen is fried, transfer baking sheet to the oven and bake Stollen for the final 4 minutes, until all slices puff up and get deep, golden brown.