Cut in butter with a pastry blender until mixture resembles coarse meal.
Stir in cheese and poppy seeds.
Make a well in the center of mixture.
Combine eggs, milk, and mustard. Add to dry ingredients, stirring just until moistened.
Spoon batter into a greased and floured 9 x 5-inch loaf pan.
Bake at 350 degrees for 1 hour and 10-15 minutes or until a wooden toothpick inserted in center comes out clean. (After 50 minutes you can tent the loaf with aluminum foil to prevent over browning on top.)