Preheat oven to 350�F (180�C) and grease a 9-inch springform pan. Set aside.
Puree half of the apricots with lemon juice and set aside.
Quarter the remaining apricots.
Cream butter and sugar in a stand mixer until light and fluffy.
Add eggs one at a time, then vanilla extract and beat until combined.
In a small bowl, mix flour, baking powder, cinnamon, and salt. Add to the mixture and beat until just combined.
Add pureed apricots to the batter and beat until just combined.
Transfer batter to the prepared pan, arrange quartered apricots on top, and bake for 55-60 minutes. Cool, then dust with powdered sugar.