Preheat the oven to 350°F (175°C) and spray a loaf pan with non-stick baking spray or line 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 for about 1 minute. Then add in the butter and cream for 3-4 minutes.

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

Add in the canola oil, lemon juice, and vanilla extract, mixing until well combined.

Turn the mixer to low, add half of the flour mixture, then add the 1/2 cup of half and half, followed by the remaining flour. Mix until just combined.

Remove the bowl from the mixer and gently stir to ensure everything is combined. Spread the batter into the prepared loaf pan.

Bake the loaf for 45-50 minutes or until golden brown and a toothpick comes out clean, though a few moist crumbs are acceptable.

Remove the loaf from the oven, let it cool for 10-15 minutes, then loosen the edges, and transfer to a cooling rack.

In a bowl, mix powdered sugar, lemon juice, and half and half until smooth. Drizzle over the cooled loaf.