There is nothing more quintessentially breakfast than blueberry muffins. For me a blueberry muffin has to be chock full of contrasts. It should have enough sweetness to feel decadent, but balanced by the tartness of the blueberries and lemon zest. A perfect muffin also has a top that has a thin crust of spiced streusel and under it is the tender muffin, stuffed with fruit. Muffins are super easy to make, but to have a tender crumb, that doesn't become tough, you need to mix it just enough to incorporate everything evenly, but stop before you develop too much gluten.