Preheat oven to 350°F (175°C). Spray an 8x4-inch loaf pan with floured cooking spray, or grease and flour the pan; set aside.

To a small bowl, add the diced apple, 1 tablespoon granulated sugar, and 1 heaping teaspoon cinnamon. Stir to combine; set aside.

To a separate small bowl, add the 0.25 cup light brown sugar (packed) and 1 heaping teaspoon cinnamon. Stir to combine; set aside.

To a large bowl, add the large egg and 0.33 cup granulated sugar, and whisk vigorously until smooth and combined, about 1 minute.

Add the 0.25 cup canola or vegetable oil, 0.25 cup sour cream or Greek yogurt, and 1 teaspoon vanilla extract. Whisk until smooth and combined.

Add the 1 cup all-purpose flour, 1 teaspoon baking soda, and 0.5 teaspoon salt. Stir until just combined; do not overmix.

Turn half the batter out into the prepared loaf pan, smoothing the top lightly with a spatula. Note that there isn’t a lot of batter, so ensure you don't add more than half.

Evenly sprinkle half the apple mixture over the batter in an even, flat layer; set the remainder aside.

Evenly sprinkle half the cinnamon-brown sugar mixture over the apples; set the remainder aside.

Add the remaining batter, smoothing the top lightly with a spatula, making sure to push it into all corners.

Evenly sprinkle the remaining apple mixture on top.

Evenly sprinkle the remaining cinnamon-brown sugar mixture.

Place the loaf pan on a baking sheet (as insurance against overflowing apple juice) and bake for about 40 to 48 minutes (I baked 43 minutes), or until the top is domed, set, and a toothpick inserted in the center comes out clean or with a few moist crumbs but no batter. Note that if you go too far down, you'll hit juicy apples. The apples on top will be juicy with slight bubbling. In the last 10 minutes of baking, tent the pan with foil (loosely drape a sheet of foil over the pan) to prevent excessive browning on the top and sides of the bread before the center cooks through.

Allow the loaf pan to cool on top of a wire rack for at least 30 minutes (I cooled overnight in the pan) before turning it out onto the rack to cool completely before glazing.

In a small bowl, add the 1 cup confectioners' sugar and slowly drizzle in the cream or milk, whisking until smooth and combined. Add milk as necessary for desired consistency (about 2.5 tablespoons).

Evenly drizzle the glaze over the bread before slicing and serving. Extra glaze can be spread on the cut surface of the bread like you’d spread butter on toast; or you can halve the glaze recipe if you’re not a glaze person. Glazed items can be kept at room temperature, but if you're concerned, drizzle glaze only over the portion of bread you plan to consume immediately.