Yield: 2 cakes; 16 to 18 servings
For the sweet dough:
1/4 cup whole milk
2 teaspoons active dry yeast
6 tablespoons (3/4 stick) unsalted butter, at room temperature, plus more for pan
3 tablespoons granulated sugar
3/4 teaspoon salt
1 3/4 cups all-purpose flour
For the filling:
3/4 cup (1 1/2 sticks) butter, softened
1 1/2 cups granulated sugar
1/2 teaspoon salt
1/4 cup light corn syrup
1 1/2 teaspoons vanilla extract
2 eggs, at room temperature
1/4 cup whole milk, at room temperature
1 cup cake flour
Powdered sugar, for dusting
1. Make the dough. Heat 1/4 cup milk until barely lukewarm, about 100 degrees. Put milk in a small bowl; sprinkle yeast evenly over milk. Let sit for 5 minutes, then stir to dissolve. Set aside.
2. In the bowl of a stand mixer fitted with a paddle attachment, beat 6 tablespoons butter, 3 tablespoons sugar and 3/4 teaspoon salt on medium speed until light and fluffy, about 3 minutes. Add 1 egg and beat until incorporated, 1 to 2 minutes. Scrape down the bowl.
3. Add all-purpose flour in three additions and the milk mixture in two additions, beginning and ending with the flour. Be sure to scrape the bowl of the milk mixture so that all yeast transfers to the dough. After each addition, beat on the slowest speed to combine, scraping the bowl occasionally. After the final portion of flour has been incorporated, increase the speed to medium-low and beat for 5 minutes or until dough is smooth and slightly elastic.
4. Butter two 8-inch-square pans or two 9-inch-round pans; and press and stretch the dough into the pans. (If the dough resists stretching, covering the pan and allowing the dough to rest for 15 minutes or so should help.) Cover loosely with plastic wrap and allow the dough to rise for 2 hours.
5. Make the filling. Shortly before the dough is done rising, combine 3/4 cup butter, 1 1/2 cups sugar, 1/2 teaspoon salt and corn syrup in the bowl of a mixer fitted with the paddle attachment. Beat on medium speed until light, about 3 minutes.
6. Scrape down the bowl; add the vanilla extract and 1 egg. Beat until combined, then beat in the remaining egg. Add 1/4 cup milk and cake flour and mix to combine on low speed. Scrape down the bowl and give the mixture a final stir.
7. When the dough is done rising, preheat the oven to 350 degrees. Cover the dough with dollops of topping, dividing evenly between cakes. Spread topping almost to the edges. Bake for about 20 to 25 minutes, until topping is crisp and golden brown. (Topping will melt and spread as it bakes.)
8. Let cake cool in the pans on a rack. Sprinkle with powdered sugar just before cutting and serving.
Per serving (based on 18): 275 calories; 13g fat; 8g saturated fat; 65mg cholesterol; 3g protein; 37g carbohydrate; 21g sugar; 0.5g fiber; 180mg sodium; 20mg calcium.