Lingonberry (cowberry) Hazelnut Coffee Cake

Heat oven to 350F. Mix flour, 1 cup sugar, baking soda, baking powder and salt in large bowl. Cut in butter using 2 knifes, until mixture resembles coarse crumbs. Reserve 1/2 cups crumb mixture. Add eggs, buttermilk and vanilla to remaining crumb mixture. Beat with electric mixer on medium speed until well blended. Stir in nuts, 1 tablespoon sugar and cinnamon into reserved crumb mixture. Spoon 1/3 of the batter into greased 9- or 10-inch tube pan. Spoon 1/2 of the jam over center of batter and sprinkle with 1/3 of the reserved crumb mixture. Repeat layers. Top with remaining batter; sprinkle with remaining reserved crumb mixture. Bake 45 to 50 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pan. Cool completely on wire rack. Makes 10 to 12 servings. Note: For North American users, "sour milk" is not milk that's gone bad: it's milk which has been purposely soured by adding buttermilk and letting it incubate for a day in a warm place (at home), or (when made commercially) inoculated with a similar culture, usually something like Streptococcus lactis, Lactobacillus cremoris, or another of the "milk-friendly" bacteria. "Sour milk" made this way is thicker than normal milk, but not as thick as sour cream (which it resembles in taste). For those of us in countries where commercially made sour milk / sauermilch or its variants can't be bought in the supermarket, buttermilk is the closest substitute.