Preheat the oven to 325 degrees F. Spray a 9-inch cake pan with cooking spray and line the bottom with a parchment circle.
Mix the cake batter per package instructions, substituting olive oil for the called-for vegetable oil or butter. Stir in the lemon zest.
Pour the batter into the prepared cake pan. Bake until the cake is light golden and a tester inserted in the center comes out clean, about 40 minutes. Let cool completely in the pan, about 20 minutes. Invert the cake onto a stand or plate and remove the parchment.
Stir together the confectioners' sugar and lemon juice to make a smooth, pourable glaze. Pour the glaze over the center of the cake and spread to the edges so some drips down the sides. Arrange or mound the raspberries in the center of the cake and serve.