Step 1

First, spray 2 6-ounce ramekins very well with cooking spray, and set them on a mini baking sheet.

Step 2

Preheat the oven to 350.

Step 3

In a small bowl, whisk together the sugar, flour, baking powder, baking soda, and pinch of salt. Set aside.

Step 4

In a medium bowl, whisk together the egg yolk, sour cream (or yogurt), oil, lemon zest, and lemon juice.

Step 5

Add the dry ingredients in two batches to the wet ingredients, and stir gently to combine.

Step 6

Divide the mixture between the two ramekins.

Step 7

Bake for 20 minutes, or until a toothpick inserted comes out clean.

Step 8

While the cakes cool, make the frosting: whisk together all ingredients, adding more lemon juice to thin it out to a pourable consistency.