Preheat the oven to 350˚F. Line a 9-inch round pan with removable bottom with a circle of parchment. Using baking spray, coat the sides of the pan. I also spray a little baking spray on the bottom, underneath the parchment to help hold it in place.
PREPARE THE STRAWBERRY JAM: Combine cornstarch & water in a bowl to make a slurry. Mix the strawberries & sugar in a small saucepan. Cook over low heat until the strawberries release their juices; about 5 minutes. Then add the cornstarch slurry & stir until well-combined Stir for another minute or two until it has thickened. Remove from heat & cool to room temperature while you prepare the rest of the cake.
PREPARE THE CREAM CHEESE FILLING: Using a hand mixer, in a medium size bowl, beat the cream cheese on medium speed for about 30 seconds until smooth. Add in the sugar & egg & beat until well-combined. Set aside.
PREPARE THE CAKE: Combine the flour & sugar in a stand mixer. Cut in the butter with the paddle attachment on low until mixture resembles coarse crumbs. Measure ¾ cup of the mixture & set aside. Add the baking soda, baking powder & salt to the remaining mixture.
In another bowl, whisk sour cream, egg & vanilla until well-blended. Add this wet mixture to the dry mixture until just incorporated. Will be thick & lumpy. Scrape bowl as needed.
ASSEMBLE THE CAKE & BAKE: Spread the cake batter in the pan coming up the sides making a border & leaving a well in the center. Pour cream cheese mixture in the center over the cake batter, being careful not to go beyond the border. Spread the strawberry jam on top of the cream cheese mixture. Sprinkle the remaining ¾ cup crumbs over the strawberry filling.
Bake for 50-60 minutes until the center is set & doesn't jiggle. Cool in the pan on a wire rack for 20 minutes before removing the cake.