Preheat oven to 350. Butter and flour an 8 inch round cake pan. In a medium bowl, whisk together flour, salt, baking powder, and baking soda.
With an electric mixer, beat butter and sugar until light and fluffy. Add eggs one at a time, beating after each additiona until incorporated; mix in vanilla. With mixer on low speed alternately add flour mixture in three parts and buttermilk in tow, beginning and ending with flour mixture. Mix just until smooth (do not over mix).
Pour batter into prepared pan; smooth top. Bake until a toothpick inserted in center comes out clean (30-40 minutes). Cook 15 minutes in pan; turn cake onto cooling rack to cool completely. Using a long serrated knife, halve cake horizontally.
While cake is cooling, combine strawberries and jam in a medium bowl.
Line sides of a 9-inch spring form pan with a strip of waxed paper. Wrap outsides of pan with plastic wrap. Center the bottom half of cake in the pan, cut side up.
Spread 1 1/2 pints of ice cream over the top and down around sides. Spread strawberry mixture on ice cream, leaving 1 inch border. Set top half of cake over it.
Spread remaining ice cream over top and down around sides of cake. Tap cake on counter to help ice cream settle. Smooth top and freeze until firm, at least 6 hours or up to 2 weeks if covered. To serve remove plastic from pan, unmold cake, and peel off waxed paper. Let cake rest at room temperature for 15 minutes before slicing.