Begin by heating your oven to 375°F (190°C) and prepare a baking sheet by covering it with parchment paper.

In a sizable bowl, combine the flour, sugar, baking powder, and salt by whisking them together thoroughly.

Add the cold cubed butter to the flour mixture and use your fingers or a pastry blender to work the butter into the flour until the mixture resembles coarse crumbs.

In another bowl, blend the milk and egg together with a whisk. Pour this into the flour and butter mixture, stirring until just combined.

Fold in the grated cheddar and mozzarella cheeses until evenly distributed.

Once your dough is mixed, transfer it to a surface dusted with flour and gently knead it 4-5 times. Form the dough into a circular loaf shape and place it onto the baking sheet you prepared earlier.

Place the loaf in the oven you've already heated and let it bake for 25-30 minutes. The bread should turn a golden brown, and it's ready if a toothpick inserted into the center comes out clean.

After baking, allow the bread to cool on a wire rack for about 10 minutes before you cut into it. Garnish with chopped parsley before serving.