Combine the melted butter with the sour cream, buttermilk, eggs, vanilla bean paste and vanilla extract. Whisk until well combined.
Pour the wet ingredients into the dry ingredients. Mix until just combined. Gently fold in the white chocolate chunks and frozen berries.
Line your 12-cup muffin pan with muffin liners. Scoop muffin batter into each muffin cup. Add a scoop of white chocolate streusel to the top of each muffins.