Preheat the oven to 350°F (175°C). Grease 4–5 cleaned 15-ounce cans or a 9x5-inch loaf pan with nonstick spray.

Place the raisins in a bowl and pour boiling water over them. Let them sit for about 10 minutes until plumped, then drain.

In a large bowl, mix together the whole wheat flour, all-purpose flour, sugar, baking powder, and salt. Beat in the egg.

In a separate bowl, whisk the baking soda into the buttermilk, then stir in the molasses.

Fold the wet mixture into the dry ingredients until just combined, then gently fold in the plumped raisins.

Pour the batter into the prepared cans or loaf pan, filling them only halfway. Tap gently on the counter to remove air bubbles.

Place the cans or loaf pan on a baking sheet. Optionally place another baking sheet on top to prevent the bread from rising too high.

Bake for about 50 minutes. Remove the top baking sheet if using and continue baking for another 10 minutes, or until a toothpick inserted in the center comes out clean.

Remove from the oven and run a knife around the edges to loosen. Carefully remove the bread and cool on a wire rack.

Slice and serve warm with butter or cream cheese.