Step 1

Preheat the oven to 350˚F. Butter and flour a 9-by-5-inch loaf pan.

Step 2

In a medium bowl, toss the apple chunks with the cinnamon, 1/4 cup of the sugar, and 1 tablespoon of the flour. i

Step 3

In a large bowl, whisk together the baking powder, salt, baking soda, remaining 3/4 cup sugar, and remaining 1 3/4 cups flour.

Step 4

In another medium bowl, whisk together the vegetable oil, buttermilk, vanilla, and eggs, then add to the flour mixture and mix until just combined. Fold in the apples (and any accumulated juices) and walnuts. Pour into the prepared loaf pan and spread evenly.

Step 5

Cut the remaining apple crosswise through the center to make 3 thin slices (1/8 inch thick); remove the seeds. Shingle the slices across the top of the loaf, gently pressing them into the batter.

Step 6

Bake until a toothpick inserted into the center of the bread comes out clean, 1 hour to 1 hour 10 minutes. Let cool for 10 minutes in the pan, then carefully remove the bread to a wire cooling rack.

Step 7

Heat the jam in the microwave until loosened and brush it on the warm bread. Let cool completely.