Preheat the oven to 350°F. In a large bowl, use a hand mixer or stand mixer to cream the shortening and sugar until light and fluffy, three to five minutes. Beat in the eggs and vanilla.

In a separate bowl, whisk together the flour, baking soda and salt. Gradually add the flour mixture to the shortening mixture, beating just until combined. Editor’s Tip: Don’t overmix when combining the wet and dry ingredients. You risk overdeveloping the gluten in the flour, which can lead to dense, tough loaves. Instead, mix just until everything is combined—there should still be a few lumps.

Using a rubber spatula, fold in the bananas just until combined. Fold in the blueberries until evenly dispersed, being careful to not overmix the batter.

Pour the batter into three greased 5-¾x3-inch loaf pans. Bake the loaves until a toothpick inserted in the center comes out clean, 40 to 45 minutes. Cool the loaves at room temperature in their pans on a wire rack for 10 minutes. Remove the loaves from the pans, and allow them to cool completely to room temperature.