Position a rack in the lower-middle of the oven and heat to 350°F (180°C). Butter and flour a 9 by 5 inch (22 by 12 cm) loaf pan, or line the bottom with parchment paper.

In a large bowl, whisk the yogurt, sugar, and eggs until smooth, about 1 minute. Add the oil and vanilla and whisk until fully incorporated. The batter will be thick but pourable.

Spoon the flour into a measuring cup and level it with a knife; do not scoop. Sift the flour, baking powder, and salt over the wet ingredients. Fold with a rubber spatula just until combined. Do not overmix.

Pour the batter into the prepared pan and smooth the top. Bake for 45 to 50 minutes, until the crust is deeply golden, the center has cracked, and a skewer inserted in the middle comes out clean.

Cool the cake in the pan for 15 minutes, then turn it out onto a wire rack and cool completely before slicing.

For the lemon version, rub the Meyer lemon zest into the sugar with your fingers for 30 seconds before adding the yogurt and eggs; the sugar should look fragrant and slightly damp.

Make the glaze by whisking the sifted powdered sugar and fresh lemon juice in a small bowl until smooth and pourable.

As soon as the cake is out of the oven, poke the top all over with a thick skewer or chopstick. Slowly pour the glaze over the hot cake, letting it soak in. Cool 15 minutes in the pan, then turn the cake out.