Add the sugar, flour, baking powder, baking soda, salt, and lemon zest to a large bowl. Stir everything together with a spatula.

In a separate bowl, combine the wet ingredients: eggs, milk, sunflower oil, and vanilla extract. Whisk until smooth.

Pour the wet mixture into the dry ingredients and fold together with a spatula until just combined. The batter can still be a little lumpy. Cut the blackberries into smaller pieces. I usually halve them.

Add a little batter to each muffin liner and place a few blackberry pieces on top. Add more batter and more berries. Layering the batter and fruit helps distribute the berries evenly throughout the muffins. It’s also easier with delicate fruit like blackberries.

I made two layers of batter and two layers of berries. Finish with a few blackberry pieces on top for decoration. You can fill muffin liners almost to the top.