Preheat the oven to 350°F (175°C). Spray a loaf pan with non-stick baking spray or line it with parchment paper.

In a medium mixing bowl, whisk together the flour, cornstarch, baking powder, and salt; set aside.

In a mixer bowl, mix the sugar and lemon zest together for a minute. Add the butter and cream with the lemon sugar mixture for 3-4 minutes.

Add the eggs and the extra yolk one at a time, beating after each addition.

Add canola oil, lemon juice, and vanilla extract; mix until well combined.

Turn the mixer to low, add half of the flour, then half and half, and the other half of the flour, mixing until just combined.

Remove the bowl from the mixer and gently stir, scraping the bottom to ensure everything is combined, then spread the batter into the prepared loaf pan.

Bake the loaf for 45-50 minutes or until the top is golden brown and a toothpick comes out just about clean.

Remove the loaf from the oven, let it cool for 10-15 minutes, then loosen around the edges, remove from the pan, and place on a cooling rack until completely cool.

In a small bowl, whisk together powdered sugar, lemon juice, and half and half until smooth. Drizzle the glaze over the cooled loaf.