The yummiest one-bowl (ish) Easy Raspberry Muffins start with a moist sour cream muffin batter that is loaded with lemon and bursting with fresh raspberries (frozen raspberries can be used too!). Each muffin is topped with buttery, crispy streusel topping (perfection). Lots of tips on getting a nice, tall muffin top as well as an optional overnight batter rest so you can have fresh-baked muffins in the morning!