Apple Cheesecake Muffins Questions

Which apples work best in these muffins?

Use a firm, slightly tart baking apple that holds its shape, since the diced pieces sit in the batter for the full 25-30 minutes. Very soft or mealy varieties collapse into mush and release extra moisture into the crumb. For the thin slices on top, cut them evenly so they bake through and brown at the same rate.

Can I use cream cheese instead of quark, and does it change anything?

Yes - the recipe allows either, but use unsalted cream cheese so the topping stays sweet. Cream cheese is thicker than quark, so let it come to room temperature and stir it smooth with the sugar, egg yolk, cornstarch and vanilla before spooning it on. Quark gives a lighter, tangier topping; cream cheese bakes up denser and richer.

Why did my cheesecake topping crack or sink into the muffin?

Sinking usually means the cups were filled too full with batter or the topping was spooned onto a very loose batter - fill the liners only two-thirds to three-quarters so there is a stable surface for the dollop. Cracking comes from overbaking, so pull the muffins once they are golden brown rather than pushing to the far end of the 25-30 minute range. The cornstarch in the topping helps it set, so do not leave it out.

How do I store them and how long do they keep?

Because of the quark or cream cheese topping, these need to go in the fridge in an airtight container rather than sitting out on the counter. Let them cool completely first, otherwise trapped steam makes the liners soggy and the topping wet. Dust with powdered sugar only just before serving, since it dissolves on the moist topping within a short time.

Can I prepare anything ahead of time?

The cheesecake mixture can be stirred together in advance and kept covered in the fridge, then stirred briefly before spooning it on. The muffin batter itself is best mixed right before baking, because the baking powder starts working as soon as it meets the milk and eggs. Slice the half apple for the topping at the last minute or toss it with a little of the cinnamon sugar so it does not brown while you wait.