Can you make the muesli in advance?

I make my Bircher meusli the night before including the apple, and I've never had trouble with browning. I add the fresh fruit and nuts when I'm serving. I often make it one evening and keep it for several days in a tightly sealed container too use for the week. Frankly, without the oats soaking overnight in the milk and yogurt, they would be a little "raw" to me. I do find that the liquid absorbs overnight and the mix can thicken up so I usually add a little more milk when serving. http://food52.com/recipes/21527-my-coffee-group-s-favorite-bircher-meusli

The original Bircher müsli is meant to be made ahead. the oat mixture is prepared with the liquids the night before and the fresh fruit is added just before serving. For this recipe, you might want to add the apples and almonds just before you serve--so the apples don't turn brown and the almonds stay crunchy. As the seasons change, you can use more seasonal fruits and enjoy müsli throughout the year.