Lemon Rosemary Coffee Cake

My mother baked this Sunday for my father's unveiling.  It was delicious.  The recipe came from a recent Southern Livinjg magazine.

3 large lemons
2 cups flour
1 1/4 cups sugar
1/2 tsp salt
1/2 cup very cold butter, cubed
1 tsp baking powder
1 tsp baking soda
3/4 cup butermilk*
1 egg
1 1/2 tsp chopped fresh rosemary
1 (10 oz) jar of lemon curd
Powdered sugar
Garnishes: fresh rosemary sprigs, lemon slices

Preheat oven to 350.
Lightly grease bottom and sides of 9 inch springform pan.  Line bottom with parchment paper.
Grate zest from lemons equal to 1 Tbsp.  Cut lemons in half; squeeze juice from lemons into a bowl to equal 5 Tbsp lemon juice.
Combine flour, sugar and salt in a bowl of food processor.  Pulse 3 to 4 times or until blended.  Add butter; pulse 6 to 7 times or until mixture resembles coarse crumbs.  Reserve 1 cup flour mixture.
Transfer remaining flour mixture to bowl of a heavy duty electric stand mixer.  Add baking powder and baking soda; beat at low speed until well blended.  Add buttermilk, egg, and 1/4 cup lemon juice; beat at medium speed1 1/2 to 2 minutes or until batter is thoroughly blended, stopping to scrape the bowl as needed.  Stir in rosemary.  Spoon half of batter into prepared pan. 
Whisk lemond curd in a small bowl one minute or until loosed and smooth; carefully spread over batter in pan.  Top with remaining half of batter.
Stir together reserved lemon zest.  1 Tbsp lemon juice, and 1 cup flour mixture; sprinkle lemon zest mixture over batter.
Bake at 350 for 45 to 50 minutes or until a long wooden pick inserted in center comes out clean.
Let cool in pan or a wire rack 10 minutes.  Gently run a sharp knife around edge of cake to loosen; remove sides of pan.  Cool cake completely on wire rack about 1 hour.
Dust with powdered sugar just before serving.
*Greek yogurt may be substituted.