Sweet Potato Cake with Browned Butter Toffee Glaze

Ingredients

• 1/2 cup pecans, coarsely chopped
• 1 tablespoon granulated sugar
• 1/2 teaspoon coarse sea salt, more or less according to taste (optional)
• 1/4 cup (2oz/ 57g) unsalted butter
• 1/2 cup (3 1/2oz/ 99g) packed brown sugar, light or dark
• 1/4 cup heavy whipping cream
• 1 3/4 cups (7.4 oz/ 210g) all purpose flour
• 1 teaspoon baking powder
• 3/4 teaspoon baking soda
• 1/4 teaspoon salt
• 1 1/4 teaspoons cinnamon
• 1/8 teaspoon ground nutmeg
• 1/8 teaspoon ground ginger
• 1/2 cup plus 2 tablespoons (5oz/ 142g) unsalted butter
• 3/4 cup (5 1/4oz/ 149g) granulated sugar
• 1/2 cup (3 1/2oz/ 99g) packed brown sugar, light or dark
• 2 eggs, at room temperature
• 1 1/4 teaspoons vanilla extract
• 1 cup (8oz/ 227g) sweet potato puree (from roasting about 12oz raw sweet potatoes)
• 1/4 cup buttermilk

Instructions

1. 1

   Adjust oven rack to lower middle position and...: Adjust oven rack to lower middle position and preheat oven to 390F/ 200C.

2. 2

   Place the butter in a light colored skillet...: Place the butter in a light colored skillet or saucepan over medium heat until melted. Continue cooking, swirling the pan constantly or stirring with a heatproof rubber spatula, until the butter is dark golden brown and has a mezmerising nutty aroma.

3. 3

   Transfer to a small bowl, cover and place...: Transfer to a small bowl, cover and place in the freezer, giving it a stir every now and then, for about 45 minutes or until it solidifies but is still soft and pliable. Once it reaches this consistency, keep it out at room temperature until ready to use. If it gets too solid and cold, give it a quick zap in the microwave to loosen but not melted. (If making a day in advance, place in the fridge instead of the freezer and let it come to room temperature before using). Meanwhile roast the sweet potatoes.

4. 4

   With a sharp knife, pierce 12 oz of...: With a sharp knife, pierce 12 oz of sweet potatoes 3 or 4 times to allow steam to escape. Wrap each sweet potato individually with foil. Place on a baking sheet and transfer to the oven to bake until very soft, 45 to 60 minutes. To test for doneness, a sharp knife inserted in the thickest part of the sweet potato should pass through very smoothly and without any resistance.

5. 5

   Take the sweet potatoes out of the oven...: Take the sweet potatoes out of the oven and allow them to rest until cool enough to handle. Reduce the oven temperature to 350F/180C. Remove and discard the foil, then slit the sweet potato skin. Using a spoon, scoop out the cooked sweet potato flesh, discarding the skin. Measure out 1 well packed cup (8oz) of sweet potatoes; you might end up with some extra (save for another use). Transfer the sweet potatoes to a medium bowl, and using a fork or potato masher or ricer, mash the 1 cup sweet potatoes until very smooth. (At this point, the mashed sweet potatoes could be stored in the fridge overnight. Bring to room temperature before using in the cake).

6. 6

   Add cold buttermilk to the warm sweet potatoes...: Add cold buttermilk to the warm sweet potatoes (to cool it down) and the vanilla and mash together to incorporate. Set aside to cool to room temperature (a little warm is ok), while preparing the rest of the cake.

7. 7

   Make sure the oven is preheated to 350F/180C.

8. 8

   Spray a 9-inch round pan with non-stick cooking...: Spray a 9-inch round pan with non-stick cooking spray, line with a parchment paper round, then spray once again.

9. 9

   In a large bowl, whisk together the flour,...: In a large bowl, whisk together the flour, baking powder, salt, baking soda, cinnamon, nutmeg and ginger. Set aside.

10. 10

    In the bowl of a stand mixer fitted...: In the bowl of a stand mixer fitted with the paddle attachment (or handheld mixer) beat the browned butter on medium high speed until creamy, about 1 minute.

11. 11

    Gradually add both sugars and cream together until...: Gradually add both sugars and cream together until lightened in both color and texture; 3 to 5 minutes.

12. 12

    Add the eggs, one at a time, mixing...: Add the eggs, one at a time, mixing well after each addition.

13. 13

    On low speed, add one third of the...: On low speed, add one third of the flour mixture, followed by half of the sweet potato mixture, then another third of the flour mixture, followed by the remaining sweet potato mixture and ending with the flour mixture, mixing just until combined between each addition. Turn the mixer speed to medium and give the batter one final mix for about 15 minutes until everything is well combined and smooth. Do not overmix.

14. 14

    Pour the batter in the prepared pan and...: Pour the batter in the prepared pan and smooth out with a spatula as evenly as possible. Bake until the cake's center springs back when lightly touched, a toothpick comes out of the center clean and the cake starts to pull away from the sides, 30 to 35 minutes.

15. 15

    Let cool in the pan for 15-20 minutes...: Let cool in the pan for 15-20 minutes then turn onto a wire rack to cool completely before glazing. Meanwhile make the browned butter toffee glaze (recipe below).

16. 16

    When ready to glaze, place the cake on...: When ready to glaze, place the cake on a rimmed serving platter or cake stand. Pour the slightly cooled toffee glaze over the surface of the cake, allowing excess to drip around the sides.

17. 17

    Allow the glaze to set for a few...: Allow the glaze to set for a few minutes then sprinkle with the candied pecans (if using). Cut into wedges and serve plain or with whipped cream, if desired. Store leftovers at room temperature in an airtight container.

18. 18

    In a small light-colored saucepan, melt the butter...: In a small light-colored saucepan, melt the butter over medium heat until melted. Continue cooking, swirling the pan constantly or stirring with a heatproof rubber spatula, until the butter is dark golden brown.

19. 19

    Immediately remove the saucepan from the heat and...: Immediately remove the saucepan from the heat and stir in the brown sugar, then add the heavy cream. Return the saucepan over the heat and bring to a simmer, stirring constantly with a whisk or heatproof rubber spatula until the brown sugar has fully dissolved; about 1 minute.

20. 20

    Let it cool briefly until thickened before pouring...: Let it cool briefly until thickened before pouring over the cake; about 15 to 20 minutes.

21. 21

    Place the pecans in a medium skillet over...: Place the pecans in a medium skillet over medium heat. Stir with a spatula until just starting to toast and beginning to smell fragrant; about 1 to 2 minutes. Immediately add the sugar, stirring frequently until the sugar starts melting, then coating the nuts. Keep stirring until the sugar turn golden brown and caramelizes. Remove from heat and sprinkle with the sea salt (if using), stirring to coat. Transfer the nuts to a place to cool completely before adding over the cake.