Preheat the oven to 365˚F and line a muffin/cupcake tin with 12 muffin liners.
Sift the flour, baking powder, and kosher salt together in a medium-sized bowl and set aside.
Place the C&H® Light Brown Sugar and lavender buds into the bowl of your food processor and process for 30 seconds. Sift into a small bowl, discarding the excess lavender buds and set aside.
In a separate large bowl, whisk together the lavender brown sugar, eggs, oil, vanilla & lavender extract, lemon zest and sour cream until well combined.
Pour the dry ingredients into the wet ingredients and gently fold together until smooth, making sure not to overmix. Fold in the blueberries until combined.
Scoop the batter into the muffin cups until ⅔ of the way full. Sprinkle with chilled crumble before baking for 23-25 minutes or until you start to see a hint of browning around the edges of the muffin. Remove from oven and let cool before icing.