Preheat oven to 325 degrees. Butter sides and bottom of a 10-inch pan (or 2 8-inch cake or springform pans) and line bottom with parchment paper. Butter paper. Place pan in freezer.

Sift flour and salt into a small bowl. Set aside. In a mixer fitted with a paddle, beat butter and granulated sugar at medium speed until fluffy, about 5 minutes. Add almond paste, a little at a time at medium speed, and beat 8 minutes.

Beat in egg yolks, one at a time, and almond extract. Mix sour cream and baking soda and add to butter mixture. Reduce mixer speed to low and gradually add flour mixture, just until blended.

Put batter in prepared pan and spread evenly. Sprinkle sliced almonds, if desired. Bake about 40 minutes, until top is golden and spring back when lightly pressed and cake shrinks from sides of the pan. Cool in pan on wire rack. Remove sides of pan and remove paper.

When ready to serve, sift confectioners’ sugar on top and slice like pie.