See below

Beat 6 Tbls. butter, 1 cup sugar, 1 egg, 1/2 tsp. vanilla together
until fluffy. Mix 1 1/2 cups cake flour, 1 tsp. baking soda, 1/2
tsp. salt together & add alternately with 1/2 cup sourdough starter,
blending after each addition. Blend in 1/2 cup milk. Pour into
buttered 8 1/2″ tube pan. Bake in 350 oven for 35 minutes. Remove
from pan & cool. Pecan glaze: Combine 3/4 cup light brown sugar, 6
Tbls. cornstarch, 1/4 tsp. salt in saucepan; stir in 3/4 cup water.
Cook, stirring constantly, until mixture thickens & boils; boil 1
minute. Add 2 Tbls. butter. Cool mixture until spreadable. Cover with
whole pecans.