Preheat oven to 350F
Cut the blackberries in half, set aside
In a large bowl measure out the flour, baking powder, soda, and salt
Stir to combine
In another smaller bowl measure out the sugar, milk, lemon juice, oil, and vanilla
Mix well
Pour the liquide mixture into the large bowl with the dry mix, gently fold to mix
Add in Blackberries and lavender and mix to combine
Pour the muffin batter into an oiled muffin tin or pour them into paper muffin liners
Let sit for 10-15 minutes to help them fluff up
Bake in the oven for 20-25 Minutes or until you poke it with a tooth pick and it comes out clean in the center