-
1
For Frosting:Mix first 4 ingredients in medium sauce-pan.
-
2
Stir over medium-low heat just until marshmallows and chocolate are melted, about 3 minutes.
-
3
Transfer to large bowl.
-
4
Mix in powdered sugar and vanilla.
-
5
Place bowl in larger bowl filled with ice and water.
-
6
Using electric mixer, beat until frosting is cool, thick and spreadable.
-
7
For the rest: Position rack in center of oven and preheat to 350F Butter two 9-inch-diameter cake pans with 1 1/2-inch-high sides.
-
8
Line bottom of pans with parchment; butter parchment.
-
9
Dust pans with flour; tap out excess.
-
10
Stir chocolate in top of double boiler over simmering water until melted and smooth.
-
11
Remove from over water.
-
12
Cool just to room temperature.
-
13
Pour yogurt into 2-cup measuring cup.
-
14
Add enough water to measure 1 1/2 cups; whisk to blend.
-
15
Whisk in vanilla.
-
16
Combine flour, sugar, butter, eggs, baking soda, baking powder and salt in large bowl.
-
17
Add yogurt mixture and melted chocolate.
-
18
Using electric mixer, beat until smooth, occasionally scraping bowl with rubber spatula, about 3 minutes.
-
19
Divide batter between prepared pans.
-
20
Bake cakes until tester inserted into center comes out clean, about 25 minutes.
-
21
Cool cakes in pans on racks 10 minutes.
-
22
Run small knife around sides of pans to loosen cakes.
-
23
Invert onto racks; peel off parchment.
-
24
Cool completely.
-
25
Place 1 cake layer, flat side up, on platter.
-
26
Spread 2/3 cup frosting over.
-
27
Top with second cake layer, flat side down.
-
28
Spread remaining frosting over top and sides of cake.
-
29
Press marshmallows around top edge in 1-inch band and 1 inch down sides from top edge of cake.
-
30
Sprinkle walnuts over center of cake.
-
31
(Can be prepared 1 day ahead.
-
32
Cover with cake dome and store at room temperature.
-
33
).
