Combine berries, brown sugar, lemon zest and juice in a medium bowl, stirring together. Set aside.
In the bowl of a stand mixer, beat the eggs on medium-high for 2 minutes. Turn mixer down to medium speed and add 1 cup of sugar, butter, vanilla, yogurt, and beat until just combined. On low speed, slowly add the flour and salt. Do not overmix.
Pour the fruit mixture into a pie dish (or 8″ cast iron skillet for a more rustic touch). Pour the cake batter on top of the fruit, smoothing it out with a spreader until all the fruit is covered. Sprinkle top with remaining 1 Tbsp of sugar. Bake for 55-60 minutes or until toothpick inserted in middle comes out clean and fruit is bubbling around edges. Serve warm or at room temperature.
