1. Preheat the oven to 400 degrees. Line muffin tray with liners or spray with non stick baking spray. Mix the streusel by mixing the butter, sugar and flour together then set aside.2. In a medium bowl, add the flour, sugar, baking powder, baking soda and salt together. Mix until well combined. Toss in the raspberries and coat with the flour mixture. Set aside. 3. In a seperate mixing bowl, mix together the melted butter, lemon zest, lemon juice, vanilla, and eggs until just combined. Add in the sour cream and mix until completely combined. 4. Pour the wet ingredients into the dry then gently fold until the batter is fully combined but being sure not to overmix. 5. Using a medium scoop, scoop heaping scoops of batter into the muffin pan. Bake at 400 for 5 minutes then drop the oven temperature doen to 350 and allow the muffins to bake for an additional 13-15 minutes or until a toothpick comes out clean. 6. Enjoy!