Ingredients
Salted Caramel Sauce
110g (1/2 cup) caster sugar
120ml (1/2 cup) 35% heavy/whipping cream
45g (3 tbsp) unsalted butter
1/2 tsp kosher salt
Cake
180g (1.5 sticks) unsalted butter, melted, slightly cooled, divided, plus more, room temperature, for pan
155g (1.25 cup) cups all-purpose flour plus more for pan
4 firm (about 1kg / 2lb), tart apples (ex Braeburn), peeled, cored, sliced 1cm / 1/2” thick
2 tbsp plus 220g (1 cup) caster sugar, divided
1 tsp baking powder
3/4 tsp kosher salt
1 tsp finely grated lemon zest
3 large eggs
Preparation
Salted caramel sauce
Bring sugar and 60ml water (1/4 cup) water to a boil in a small saucepan over medium-high heat, stirring to dissolve sugar. Boil, swirling pan occasionally and brushing down sides with a wet pastry brush, until mixture turns a deep amber color, 8–10 minutes. Remove from heat and slowly add cream (mixture will bubble vigorously). Return to medium heat and cook, stirring occasionally, until smooth, about 2 minutes. Remove from heat and mix in butter and salt. Pour caramel sauce into a small heatproof jar or bowl; let cool.
Caramel sauce can be made 5 days ahead. Cover and chill.
Cake
Place rack in middle of oven and preheat to 175C/350F. Butter and flour cake pan; set aside.
Heat 30g melted butter in a large skillet over medium heat. Add apples, sprinkle with 2 tbsp. sugar, and cook, tossing occasionally, until apples are golden brown, 10–12 minutes. Arrange half of the apples in the bottom of prepared cake pan so most of it is covered (a few gaps are okay).
Whisk baking powder, salt, lemon zest, floup and remaining sugar in a large bowl. Whisk in eggs and remaining melted butter until smooth.
Pour half of batter over apples in cake pan, top with remaining apples, then pour remaining batter over. Bake cake until top is golden and a tester inserted into the center comes out clean, 40–50 minutes. Transfer pan to a wire rack and let cake cool slightly; turn out onto rack and let cool.
Serve cake with caramel sauce.
