St. Louis Gooey Butter Cake

Ingredients

• 1/4 cup whole milk
• 2 1/4 tsp active dry yeast
• 3 tbsp caster sugar
• 6 tbsp unsalted butter, softened
• 1 large egg
• 1/2 tsp fine salt
• 1 3/4 cups plain flour
• 3/4 cup unsalted butter, for the topping
• 1 1/2 cups caster sugar, for the topping
• 1 large egg, for the topping
• 1/4 cup light corn syrup
• 3 tbsp water
• 2 tsp vanilla extract
• 1 1/4 cups plain flour, for the topping
• 1/4 tsp fine salt, for the topping
• 3 tbsp icing sugar, for dusting

Before you cook

• Warm the milk to 110F, which should feel just barely warm on your wrist.
• Stir the yeast and a teaspoon of the caster sugar into the warm milk and leave it for 8 minutes, until it foams.
• Take both quantities of butter out of the fridge well ahead so they soften.
• Grease a 9 by 13 inch baking tin and line the base with baking parchment.
• Bring the eggs to room temperature.

Steps

1. Beat the 6 tablespoons of softened butter with the remaining caster sugar until pale and creamy.
2. Beat in the egg and the salt until smooth.
3. Pour in the foamy yeast mixture and mix it through.
4. Add the 1 3/4 cups of flour and mix to a soft, sticky dough that pulls together in a mass.
5. Knead the dough in the bowl for 3 minutes, until it is smooth and elastic.
6. Press the dough evenly across the base of the prepared tin with floured fingers, pushing it into the corners.
7. Cover the tin with a tea towel and leave it in a warm place for 1 hour and 30 minutes, until the dough has risen and looks puffy.
8. Heat the oven to 350F.
9. Melt the 3/4 cup of butter and let it cool for 5 minutes.
10. Whisk the melted butter with the 1 1/2 cups of caster sugar until glossy.
11. Whisk in the egg, the corn syrup, the water and the vanilla until completely smooth.
12. Fold in the 1 1/4 cups of flour and the salt, stopping as soon as the batter comes together.
13. Spoon the topping over the risen dough in dollops, then spread it gently to the edges without deflating the base.
14. Bake the cake for 32 to 38 minutes.
15. Check it when the edges are golden and set but the middle third still wobbles like a set custard when you shake the tin.
16. Cool the cake in the tin on a wire rack for at least 45 minutes so the gooey layer firms up.
17. Dust the top heavily with icing sugar and cut it into squares.