Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Grease and flour two 9x5 inch loaf pans.

Sift flour, baking soda, baking powder, salt, cinnamon, and allspice together in a large bowl; set aside.

Beat sugar and butter together in a separate bowl with an electric mixer until light and fluffy. Beat in eggs, one at a time, then mix in mashed avocado.

Stir in flour mixture alternately with buttermilk until just mixed. Fold in chopped pecans, raisins, and orange zest.

Divide batter evenly between the two loaf pans.

Bake in the preheated oven until a toothpick inserted into the center of the loaf comes out clean, about 1 hour. Allow loaves to cool in pan for at least 20 minutes before removing.