Preheat oven to 350°F (180°C). Butter an 8-inch square baking pan or spray with baking spray with flour. Line pan with parchment paper, letting excess extend over sides of pan.

In a large bowl, place sugar; add lemon zest, and rub between fingers into sugar until incorporated. Whisk in oil, vanilla, and lemon extract (if using). Add egg and egg yolk, one at a time, whisking until combined after each addition. Whisk in lemon juice; whisk in sour cream. One at a time, sprinkle baking powder, salt, and then baking soda over mixture, vigorously whisking until combined after each addition. Sift flour over mixture, and gently fold with a flexible spatula until combined. Scrape batter into prepared pan.

Bake until a wooden pick inserted in center comes out with a moist crumb or two, 40 to 45 minutes, rotating pan halfway through baking. Let cool completely in pan on a wire rack.

Using excess parchment as handles, remove cooled cake from pan, discard parchment, and place cake on wire rack. Starting in center, gently pour Lemon Glaze over cake, spreading with an offset spatula so it drips over edges. Store, tightly wrapped in plastic wrap, for up to 5 days.