In a bowl, combine the strawberries, sugar, lemon juice, and lemon zest. Let sit for 30-60 minutes to draw out the juices and create a syrup.
Cream together the butter, sugar, flour, and salt. Set aside.
Sift together flour, baking powder, sugar, and salt.
With your fingertips or a pastry blender, work in the cold butter until it resembles large breadcrumbs. Work quickly as you don’t want the butter to warm up too much.
In a separate bowl, whisk together the egg, half & half, and vanilla.
Stir the egg mixture gently into the butter and flour mixture just to combine.
Smooth the shortcake batter into the prepared pan.
Pour the strawberry mixture over the top of the shortcake.
Sprinkle the streusel over the strawberries.
Bake at 375 for approximately 30-35 minutes. Check partway through to make sure the syrup is not bubbling over or burning. You can also place a sheet pan on the rack below to catch any drips, if you like.
When testing for doneness, the standard toothpick test doesn't work well because the strawberry topping gets in the way! This cake is done when the center is set and the edges spring back to the touch.
Serve warm or at room temperature, with lots of whipped cream.
