Step 1

Preheat the oven to 350°F.

Step 2

Lightly oil and flour the bottom of a 9-inch round cake pan.

Step 3

In a small container such as a liquid measuring cup, stir together the olive oil, orange juice, milk, orange zest, and vanilla.

Step 4

Whisk the flour, sugar, baking powder, baking soda, and salt together in a large mixing bowl.

Step 5

Pour the liquid mixture into the bowl with the dry ingredients and stir the batter until almost all of the lumps are out. It doesn't need to be perfectly smooth.

Step 6

Pour the batter into the prepared cake pan.

Step 7

Bake the cake for about 25 minutes, until a toothpick inserted into the center comes out clean.

Step 8

Place the pan on a cooling rack and let the cake cool completely.

Step 9

Once the cake is cool, carefully invert it onto a plate.

Step 10

Optionally sprinkle the cake with powdered sugar. Slice and serve.