Preheat oven to 325°F. Beat butter with a heavy-duty electric stand mixer at medium speed until creamy, about 1 minute. Gradually add sugar, beating until light and fluffy, 3 to 5 minutes. Add eggs, 1 at a time, beating just until blended after each addition. Stir in lemon zest, fresh lemon juice, and vanilla bean paste.
Stir together flour, salt, and baking soda in a medium bowl. Add flour mixture to butter mixture alternately with sour cream, beginning and ending with flour mixture. Beat at low speed just until blended after each addition. Pour batter into a greased (with shortening) and floured 10-inch tube pan.
Bake in preheated oven until a long wooden pick inserted in center comes out clean, 1 hour, 15 minutes to 1 hour, 30 minutes. Cool in pan on a wire rack 10 minutes; remove cake from pan to wire rack, and cool completely, about 2 hours.
Spoon Lavender Glaze over cake. Sprinkle with lemon zest.