Autumn Delight Cake

{Sweet Potato & Ginger Layer Cake with Toasted Marshmallow Filling, Candied Pecans and Brown Sugar & Cinnamon Buttercream}

Sweet Potato & Ginger Cake Layers

Yield: two 8-inch layers (to be split in 2 each)

Ingredients

2 pounds (908 grams, about 3 large sweet potatoes)

1 1/4 cups (315 mL) sunflower oil (or vegetable, safflower, or canola)

2 cups (230 grams/8 ounces) cake flour

4 large eggs, at room temperature

2 cups (400 grams/14 ounces) sugar

2 teaspoons (8 grams) baking powder

1 teaspoon (7 grams) salt

1 tablespoon (7 grams) ground cinnamon

1 teaspoon (3 grams) ground nutmeg

1/2 teaspoon (1.5 gram) ground ginger

2 teaspoons (10 mL) pure vanilla extract

2 tablespoons (30 mL) brandy or dark rum

3/4 cup (120 grams/4 ounces) crystallized ginger chips

Method

1. Preheat oven to 350°F. Grease two 8-inch round cake pans, dust with flour, tap out excess and set aside.

2. Place the sweet potatoes on a microwave-safe plate and pierce them with a fork. Microwave until they are tender (about 7-8 minutes each side. Carefully remove the skin when cool enough to touch, and mash the flesh into a coarse puree.

3. In the bowl of an electric mixer fitted with the paddle attachment, beat the eggs and sugar together on medium-high speed (I use #6 on KitchenAid) until light and fluffy, about 5 minutes. Add the oil and beat on medium until combined. Add the cooled sweet potato puree and mix until combined.

4. Sift dry ingredients together (cake flour, baking powder, salt, cinnamon, nutmeg and ground ginger) and then add to sweet potato mixture. Mix in vanilla and brandy/dark rum. Gently stir in crystallized ginger chips.

5. Evenly distribute batter into the prepared pans (weigh them if possible with digital kitchen scale), smooth with a small offset palette knife and place in the centre of the middle rack of the oven, about 2 inches apart. Bake until a knife or skewer inserted into the center comes out clean, about 40 minutes. Let pans cool on a wire rack 10 minutes. Invert cakes onto rack and cool them completely.

Whipped Toasted Marshmallow Filling

Ingredients

12-16 standard-size white marshmallows

1 cup unsalted butter (2 sticks/227 grams/8 ounces), softened and cut into cubes

1 cup (125 grams/4 ounces) sifted icing sugar (confectioners’ or powdered)

2 tablespoons (30 mL) milk

1 teaspoon (5 mL) pure vanilla extract

7.5 ounce jar of Marshmallow Fluff (or other marshmallow cream)

pinch of salt

Method

1. Place marshmallows on cookie sheet lined with parchment paper. Place on lower rack of oven, and broil marshmallows until nice and brown on top (be sure to keep an eye on them--they burn very, very quickly), then remove tray from oven and carefully turn them over and return to oven to brown. Remove tray from oven and place on a wire rack to cool.

2. In an electric mixer fitted with the paddle attachment, whip butter for 8 minutes--it will be very pale and fluffy.

3. Add sifted icing sugar, milk, vanilla, and salt and beat for another 6 minutes.

4. Add toasted and cooled marshmallows and marshmallow cream, mixing on low speed for about 2 minutes.

5. Best used right away, but keeps well once in cake; keep at room temperature.

Brown Sugar & Cinnamon Swiss Buttercream

Yield: ~5 cups, enough for 2 "coats" of frosting an 8-inch round x 4-layer cake

Ingredients

5 large egg whites (~150 grams/5 ounces)

1 1/4 cup (250 grams/8.5 ounces) light brown sugar

1 1/2 cups (3 sticks, 340 grams/12 ounces/3/4 lb) unsalted butter, softened and cut into cubes

2 teaspoons (10 mL) pure vanilla extract

pinch of salt

a few pinches of cinnamon, to taste

Method

1. Wipe the bowl and whisk attachment of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites and brown sugar and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 140-160°F, or if you don’t have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot, about 5 minutes if you used room temperature egg whites. About 8 if they were cold.

2. With whisk attachment of mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). Switch over to paddle attachment and, with mixer on low speed, add softened butter in chunks until incorporated, and mix until it has reached a silky smooth texture (if curdles, keep mixing on medium-low and it will come back to smooth).

3. Add vanilla, salt and cinnamon, continuing to beat on low speed until well combined.

Notes:

1. Can make buttercream ahead and keep in an airtight container in refrigerator for up to one week, leaving out at room temperature when needed, re-whipping in mixer for 5 minutes.

2. Can freeze for up to 6-8 weeks. To thaw, place on counter overnight, and rewhip for 5 minutes with paddle attachment in an electric mixer.

3. If not satiny enough upon rewhip, take 1/3 of buttercream and microwave in a microwave-safe container for ~8 seconds, then add back to mixing bowl and remix with remaining buttercream.

4. For more detail about making Swiss Meringue Buttercream, you can find FAQ here and photo tutorial here.

Candied Pecans (for inside & outside of cake...or just anytime at all)

adapted from Creative Culinary

Ingredients

2 tablespoons (28 grams/1 ounce) unsalted butter

2 tablespoons (24 grams) brown sugar

1 cup (100 grams/3.5 ounces) pecan pieces

Method

1. Melt the butter in a small pan.

2. Mix in brown sugar.

3. Add the pecans and toss to coat

4. Cook on medium low heat for about 15 minutes, stirring occasionally. Be sure to watch carefully so they don’t burn.

5. Turn out onto parchment paper or aluminum foil and let cool for 5 minutes; break apart into smaller pieces if using halves.

Assembly of the Autumn Delight Cake

1. Slice both cake layers in half horizontally, so you have 4 cake layers.

2. Place the first layer on a plate, pedestal or cake board cut side up (so bottom of the cake layer is touching plate), and spread ~3/4- 1 cup of Toasted Marshmallow Filling with a small offset palette knife, leaving 1" or so around the edge. Sprinkle with a handful of candied pecans pieces.

3. Repeat step 2 until you come to the final cake layer. Place last layer face down and chill cake for 30-40 minutes.

4. Frost cake with Brown Sugar Buttercream and top with a generous handful of candied pecans and crystallized ginger (optional).

5. Can be kept at room temperature for up to 8 hours. Keep refrigerated if longer than 8 hours, but always serve at room temperature (Swiss Buttercream should never be served cold, as it goes back to a cold-butter texture).

Good luck & enjoy!

Love, Rosie xo
 
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