Mantelimuffinit

You can swap the 40 g of ground almonds for the same weight of all-purpose flour, giving you 140 g flour total. The muffins will still rise fine because the baking powder and butter do the lifting, but they lose the moist, slightly dense crumb and the nutty flavor. If you want to keep the texture, ground hazelnuts work as a one-to-one replacement.

Almost always overmixing after the flour goes in - the recipe deliberately says to add the dry ingredients and milk alternately and to mix gently. Once the flour is wet, extra stirring develops gluten and the batter loses the air you beat into the butter and sugar. Stop as soon as no dry streaks remain, even if the batter still looks a little uneven.

Let them cool completely on the wire rack first, otherwise trapped steam makes the paper liners soggy. Then keep them in an airtight container at room temperature for a couple of days; the butter and milk in the batter keep them soft. For longer storage, freeze them once cool and warm them briefly in the oven before serving, and add the powdered sugar only after warming.

It's better not to - the baking powder starts reacting as soon as it meets the milk and egg, so a batter that sits overnight bakes up flatter. Instead, mix the flour, ground almonds, baking powder, and salt in advance and leave the bowl covered on the counter. In the morning you only need to cream the butter and sugar and combine, which takes a few minutes.

Melted butter won't work the same way here, because creaming softened butter with the sugar is what whips air into the batter and keeps it light and fluffy. Cut the cold butter into small cubes and let it sit at room temperature until a finger leaves a dent, or grate it coarsely to speed things up. Cold butter also curdles the batter when the egg goes in, so give it time.