Bring the syrup ingredients to a boil and set aside.
In a bowl, whisk together the eggs, sugar, and honey.
Add the mascarpone and mix until smooth.
Pour in the lemon juice, lime juice, and oil, then mix well.
Sift in the flour and baking powder. Add the lemon and lime zest and mix just until combined.
Divide the batter between 6 muffin cups.
Bake at 180°C (350°F) for about 25 minutes, or until golden and a toothpick inserted in the center comes out clean.
While the muffins are still warm, brush them generously with the lemon syrup and sprinkle with extra lemon zest.
