Banana Toffee Cake

For cake:
1/2 cup (4 ounces or 115 grams) unsalted butter, melted and cooled slightly
1/4 teaspoon fine sea or table salt
1/2 cup (95 grams) packed dark brown sugar
6 tablespoons (75 grams) granulated sugar
1 tablespoon molasses or treacle
1 teaspoon vanilla extract
2 large eggs
2/3 cup (170 grams) mashed bananas (2 medium bananas, or about 12 ounces unpeeled)
1/2 cup (120 ml) buttermilk, well-shaken
1 teaspoon baking powder
3/4 teaspoon baking soda
1 3/4 cups (230 grams) all-purpose flour
 
For topping:
4 tablespoons (2 ounces or 55 grams) unsalted butter, cold is fine
1 cup (235 ml) heavy cream, divided (half for sauce, half for whipping)
1/2 cup (95 grams) dark brown sugar
1/4 teaspoon flaky sea salt plus more to finish
1/2 teaspoon vanilla extract
 
Make cake:
Heat oven to 350°F.  Coat 12 standard muffin cups (or an 8x8-inch square or 9-inch round pan) with butter or with nonstick spray.  In a large bowl, whisk together butter, salt, brown sugar, granulated sugar, molasses, and vanilla until combined.  Add mashed banana and whisk again.  Add eggs and whisk until incorporated, then buttermilk.  Sprinkle baking soda and baking powder on batter and whisk until combined and then (don’t skip this), whisk 10 to 20 more times, ensuring that it is very well dispersed in the bowl.  Add flour and mix only until it disappears.  Divide batter between 12 cups, or spread in pan.  Bake 14 to 16 minutes (or 25 to 27 minutes for square or round pan), until a toothpick inserted into the cakes comes out batter free.
 
While the cakes bake, make the toffee sauce:
Combine butter, 1/2 cup of the heavy cream, and sugar in a larger saucepan than you think you’ll need over medium-high heat and bring to a simmer.  Simmer, whisking frequently, for 5 to 7 minutes — the mixture thickens slightly.  Add a couple pinches of salt and vanilla.
 
And whipped cream:
In a medium-large clean bowl, beat remaining 1/2 cup heavy cream with an electric or you-powered whisk until it forms soft peaks.  Don’t add sugar to this; I promise it does not need it.
 
To serve:
Remove one warm cake from the muffin tin and either plate it dome side-up or you can cut the dome off the cake with a serrated knife and serve the cake upside-down.  If baked in one pan, allow to cool a bit before cutting into slices.  Ladle the cake generously with the toffee sauce, finish with a big dollop of the cream and a few flakes of sea salt.  Repeat with remaining cakes.
 
The sauce keeps for a week or two; it can be reheated in about 20 seconds in the microwave, just until it liquefies, or back on the stove in a small saucepan.  The cake keeps for 3 to 4 days at room temperature in an airtight container before seeming stale.  If you can gently rewarm it before serving, all the better.
 
Serves 12.
 
From SmittenKitchen.com