Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.

In a large bowl, whisk together flour, baking powder, brown sugar, and granulated sugar until evenly blended.

In a separate bowl, beat the eggs, then add milk, oil, and lemon zest; mix until well combined.

Gently pour the wet mixture into the dry ingredients and stir until just combined.

Fold in the finely chopped kale until evenly distributed throughout the batter.

Divide the batter among the muffin liners, filling each about two-thirds full.

Bake for 18-22 minutes until golden brown and a toothpick inserted comes out clean.

Let cool in the tin for about 5 minutes before transferring muffins to a wire rack.