Caramel-Peanut-Topped Brownie Cake

I messed up on this one because I overcooked the caramel. But I think this would have been a wonderful cake if I could have gotten the caramel right. So I'm going to post it anyway - because I'd make it again.

Ingredients: Cake
1 cup all-purpose flour
1 tsp. baking powder
1/4 tsp. salt
1 stick of butter (cut into 8 pieces)
5 oz. bittersweet chocolate
3 large eggs
1/2 cup packed light brown sugar
1/4 cup sugar
3 Tbs. light corn syrup
1.2 tsp. vanilla extract

Ingredients: Topping
2 cups sugar
1/2 cup water
1.5 Tbs. light corn syrup
2/3 cup heavy cream
2 Tbs. unsalted butter. at room temp.
1 cup salted, roasted peanuts

Method: Cake
1. Center a rack in the oven, and preheat to 350F.
2. Grease a springform tin (I used a 9-inch), dust the inside with flour, and line the base with parchment paper.
3. Place the pan on a baking sheet.
4. Whisk the flour, baking soda and salt together.
5. Set a heatproof bowl over a saucepan of simmering water, put the butter and chocolate in a bowl and heat, stirring occasionally, until the ingredients are just melted.
6. Remove the bowl from the heat.
7. In a large bowl whisk the eggs and sugars together until well blended.
8. Whisk in the corn syrup, followed by the vanilla.
9. Whisk in the melted butter and chocolate.
10. Still using a whisk, add the flour mix. Combine until just incorporated.
11. Pour the batter into the prepared pan. Jiggle the pan to get an even batter.
12. Bake the cake for 35-40 min, or until a thin knife inserted into the center almost comes out clean.
13. Let the cake cool for 15min on a rack.
14. Run a knife along the edges, and remove the sides of the pan. Once the cake is completely cool you can remove the base.

Method: Topping
1. Put the sugar, water and corn syrup in a medium heavy bottomed saucepan., stir to just combine the ingredients.
2. Heat, without stirring, until the caramel turns a deep amber. 5-10min, depending on the size of the saucepan and the intensity of the heat.
3. Lower the heat a bit and standing back from the saucepan, add the cream and butter.
4. Stir to combine.
5. Stir in the peanuts, and place in a pouring jug.

Method: Assembly
1. Spoon the peanuts out of the hot syrup and put them on the cake.
2. Spoon over enough hot syrup to cover the nuts,
3. Allow topping to set at room temperature (20 or so min).

From Dorrie Greenspan's Baking: From My Home To Yours, pp. 264-5.