Preheat oven to 400 degrees F with two racks in center of oven leaving enough room for muffins to rise.

Prepare two 12-cup standard muffin tins by greasing the tops with butter and spraying the inside with pan spray. Add muffin cup liners to each.

In the bowl of a stand mixer with the paddle attachment, cream butter and shortening for one minute. Add sugar and zest and cream for one minute.

With machine on medium speed, add one egg at a time to mix. Scrape sides and cream for two and a half minutes to add air into the batter. Add lemon extract, vanilla extract and lemon juice and beat to combine.

Place thawed drained blueberries in a small bowl and add two tablespoons of the bread flour and mix to combine. Set aside.

After shredding the zucchini, place in a cheese cloth and wring out as much water as possible. Place zucchini in a small bowl and add two tablespoons of the bread flour and toss to combine. Set aside.

In a separate bowl combine both flours, salt and baking powder and combine with a whisk.

With the mixer running on low, slowly add flour alternating with milk and oil until all flour, oil and milk are mixed in. Scrape and mix just long enough to combine. Do not mix further or muffins will be tough.

Remove bowl from mixer and with a wooden spoon or spatula, gently fold in blueberries and zucchini.

Using an ice-cream scoop, divide the batter between the 24 cups, filling right to the brim.

Sprinkle a little granulated sugar over the tops of each.

Bake for five minutes at 400 degrees F then reduce to 375 degrees F and continue to bake for 25-30 minutes. Ours took 28 minutes after the initial five minutes at the higher temperature.

Use a tooth pick poked into the center to test for doneness. The muffins are done when the toothpick comes out clean and the tops are lightly browned.

Let cool for five minutes, then remove each muffin to cooling racks.