Preheat the oven to 400 degrees. Line a standard muffin pan with paper liners and spray the liners with cooking spray. In a large bowl, whisk the sugar, eggs, and oil vigorously until well combined.

Add the milk and whisk until incorporated.

Add the flour to the wet ingredients, and sprinkle the baking powder, baking soda, cinnamon and salt over the flour. Combine the wet and dry ingredients by stirring gently just until combined.

Add the blackberries and fold in gently.

Divide the batter evenly among the muffin cups. Bake the muffins for about 15 minutes or until golden brown and a toothpick inserted into the center comes out clean.

Cool on a wire rack for 10 minutes, then remove the muffins from the pan and continue to cool on the wire rack. Enjoy!