Preheat the oven to 180°C and line a muffin tin with paper cases.
In a large bowl sift together the flour, sugar, baking powder and salt. Add the oats and combine.
In a small bowl beat the eggs, then add milk, melted butter, elderflower cordial, lemon zest & juice.
Pour the egg mixture into the flour mixture and combine.
Spoon the batter into the cases and bake for 20-25 minutes until the muffins are golden.
Meanwhile, make the syrup by placing the lemon juice, water, elderflower cordial and sugar in a small pan and heating it gently until the sugar has dissolved completely and it becomes syrupy.
Remove the muffins from the oven. Poke them with a skewer to make holes, then drizzle the elderflower syrup over each of them.
Top the muffins with some lemon zest and spoon over the remaining drizzle.