For the pancakes, whisk together the flour, sugar, baking powder, salt, mustard powder, paprika and cayenne in a large bowl. Whisk in the buttermilk and egg until just smooth. Stir in 3 tablespoons of the melted butter. Toss the macaroni with the remaining 1 tablespoon melted butter in a small bowl. Season with salt. Sprinkle with the Cheddar; toss to combine. Stir the macaroni mixture into the pancake batter.
Heat a griddle or large skillet over medium heat. Melt the remaining 2 tablespoons butter on the griddle. Scoop the batter with a 1/2 cup measuring cup and add as many pancakes as will fit without crowding. Cook until the bottoms are golden brown, 2 to 3 minutes. Flip and cook to brown the other side, about 1 minute more.
Once all the pancakes are done, warm the syrup in a small saucepan. Serve the pancakes with the syrup and a sprinkling of chives.