Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).

Grease a 9x5 or 8x4 inch loaf pan.

Remove casing from chorizo and chop coarsely.

Brown chorizo in a frying pan; drain excess fat and set aside.

Lightly spoon flour into a measuring cup and level it off.

In a large bowl, combine flour, sugar, dry onion, baking powder, baking soda, dry mustard, and salt.

Blend the dry ingredients well.

Using a pastry blender or two knives, cut in the softened butter until the mixture resembles coarse crumbs.

Add cheddar cheese, buttermilk, and beaten eggs to the dry ingredients.

Stir until just well blended; do not overmix.

Stir in the cooked chorizo and minced black olives.

Spoon the batter evenly into the prepared loaf pan.

Bake in the preheated oven for 40-50 minutes on the second shelf from the bottom.

Remove the bread from the pan immediately after baking.

Cool on a wire rack before slicing and serving.