I had my first bircher muesli in Switzerland, where it’s a breakfast staple. I was at a breakfast buffet, and a large bowl of what appeared to be a thick and chunky porridge was presented in the center of the table. At first glance, I was unimpressed, but at the prompting of my Swiss friend, I gave it a try. It was fresh, bright, and creamy; chock-full of fruit and nuts; and not at all stodgy. Not only did it feel healthy to eat, but it was downright delicious. Bircher muesli is essentially overnight oats. It’s a practical and healthy do-ahead meal, reflecting marvelous Swiss sensibilities. A blend of oats and milk or yogurt is muddled together and refrigerated overnight. The next morning, you thin the mixture with more yogurt or milk and fold in fruit and nuts. The result is a nutritious and tasty breakfast that will energize and …