Preheat oven to 350°F. Grease a 13- by 9- by 2-inch baking pan. In a small bowl, whisk together flour, salt, cinnamon and baking powder. In a large bowl, beat together 1 stick of butter and 2/3 cup sugar with an electric mixer until fluffy, about 3 minutes (you can also use a stand mixer fitted with the paddle attachment on medium speed). Beat in eggs. Beat in vanilla and almond extract. Beat in half the flour mixture. Beat in half the sour cream. Beat in remaining flour, followed by remaining sour cream.
Pour batter into prepared pan. Arrange peach slices along the top of the batter in three tightly packed rows.
Cut remaining butter into small dice. Sprinkle over peaches. Sprinkle remaining 1/3 cup sugar over peaches. Bake until cake has set and a tester comes out clean, about 40 minutes.