In a large mixing bowl, combine cake flour, sugar, baking soda, and salt until blended.
With mixer running, add softened butter 1 or 2 pieces at a time.
Continue beating until it resembles coarse crumbs, 1-2 minutes.
Add buttermilk, egg, yolk, and vanilla, and beat at medium speed until light and fluffy.
Fold in lemon zest.
Transfer to an 8-inch pan lined with foil (hanging over the edges) and lightly greased.
Transfer the strawberries to the coffee cake batter, scattering them across the top, and swirling lightly with a knife.
Break apart the crumb topping in pea-sized pieces and spread them into an even layer over the batter, working from the outer edges to the center.
Bake at 325 degrees for 35-40 minutes, or until crumbs are golden and a toothpick inserted near the center comes out clean.
Cool on a wire rack for at least 20 minutes before carefully removing the cake from the pan by the foil lining. Cut into 9 pieces.
Serve warm with lemon glaze.