Boil syrup ingredients in a large saucepan until reduced to 3/4 cup.
Whisk together flour, cornmeal, sugar, baking powder, baking soda, and salt in a large bowl, then stir in currants. Stir together yogurt and eggs with a fork in another bowl and stir into flour mixture with melted butter just until incorporated.
Heat a lightly greased large nonstick skillet over moderately low heat until hot.
Pour 1/4-cup measures of batter into skillet in batches, forming 3 1/2-inch cakes, and cook about 3 minutes, or until undersides are golden. Turn and cook 1 minute more, or until golden.
Transfer to a baking sheet and keep warm in a 250°F oven while cooking remaining cakes.