Pioneer Swedish Jam Cake

I am not sure if this is super authentic, and I don't recall where I got this recipe, but it sure is good!

1/2 cup butter, room temperature

1 1/4 cups sugar

3 eggs, separated

Pinch salt

1 teaspoon baking soda

1 cup buttermilk

2 1/2 cups sifted flour

1/2 teaspoon cinnamon

1/4 teaspoon cloves

1/2 teaspoon allspice

1 cup strawberry jam

Cream butter and sugar; add beaten egg yolks and salt. Dissolve baking soda in buttermilk. Sift together flour and spices and add to creamed mixture alternately with buttermilk, adding flour mixture last. Beat well and add jam. Beat egg whites in a bowl and fold into cake batter. Bake in greased and floured 8x8-inch pan at 375° F. for 35 to 40 minutes.