Preheat the oven to 350º. Spray a bundt pan with cooking spray.
Cream the butter and sugar in the bowl of an electric mixer until light and fluffy, about 2 minutes. Add eggs one at a time, beating after each addition. Add vanilla and lemon zest.
In a separate bowl, whisk together the flour, baking powder, soda and salt. Add a tablespoon of the flour mixture to the blueberries if using fresh berries. If using frozen, it's not needed but keep them frozen until ready to add.
Add a 1/3 of flour mixture to the butter mixture, alternating with yogurt, starting and ending with the flour mixture. Mix until just combined and smooth.
Gently fold in the blueberries and spoon the batter into the bundt pan, levelling off the surface so that it is even.
Bake for 45-50 minutes until the top is golden brown and a toothpick comes out clean. It should be firm to the touch.
Let cool for 10 minutes and then invert onto a wire rack.
To make the frosting, cream together all of the ingredients, except the white chocolate, with a hand mixer until creamy and smooth. Smooth over the top of the cooled cake and sprinkle with chopped white chocolate.