Blueberry Walnut Twirls

Blueberry heaven. 

1 cup room temp butter
1 1/2 cup sugar
1/2 tsp baking powder
1/2 tsp salt
2 eggs
1 tsp vanilla
3 1/2 cups flour
1/2 cup blueberry jam
1 1/2 tsp cornstarch
1/2 cup very finely chopped walnuts

1. In mixer, beat butter, sugar, baking powder, salt. Scrape sides of bowl until combined.
2. Add eggs, vanilla then flour. Split dough in half and chill 1 hr min.
3. Heat jam and cornstarch until thickened and bubbly. Remove from heat, mix in walnuts.
4. Roll half dough to 11x11 square. Cover with jam mix leaving edges clean. Roll into spiral, wet edges and pinch to seal. Chill or freeze for 4 hrs to 3 days.
5. Cut into 1/4" slices, place on greased cookie sheet in 375 oven for 10-12 mins. Cool on sheet for 2 mins then transfer to rack.