Preheat oven to 350°F (175°C). Grease three loaf pans.

In a small bowl, pour boiling water over raisins and let stand to plump.

In a large bowl, beat eggs and sugar until light and fluffy.

Add vegetable oil and pork and beans to the egg mixture.

Mix until the beans are thoroughly mashed and incorporated.

In a separate bowl, sift together flour, soda, cinnamon, and baking powder.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Stir in vanilla and chopped nuts, if using.

Drain the raisins and add them to the batter.

Mix well to distribute all ingredients evenly.

Pour the batter into the prepared loaf pans, dividing evenly.

Bake for 45 to 50 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the bread cool in the pans for a few minutes before transferring to a wire rack to cool completely.