Preheat oven to 425°F
Spray 8 inch x 8 inch cake pan with non-stick cooking spray.
In large bowl, combine flour, cornmeal, brown sugar, baking powder, mustard seed and salt. Mix well.
In another bowl, combine milk, oil, prepare mustards, maple syrup, beaten egg, onions and dill. Pour mixture into dry ingredients and stir just until moistened.
Gently fold in ham. Pour batter into prepared cake pan.
Bake until light brown on top and skewer inserted in middle of cornbread comes out clean, about 20 minutes.
Remove from oven. Let cool 10 minutes before cutting into three lengthwise, then three crosswise, forming nine squares.
Store in an airtight container for up to 2 days or freeze up to 2 months.