Step 1In a large, heavy-bottomed saucepan, cook the butter, sugar and honey to a deep, dark caramel color over medium-high heat, stirring frequently. Meanwhile, bring the cream, salt and vanilla to a gentle simmer in a separate saucepan. When the sugar mixture is ready, carefully and slowly whisk in the hot cream (it will bubble, and it could spill over the pan if poured too quickly). Remove from heat and set aside. This makes about 3 cups toffee sauce.
Step 1Heat the oven to 350 degrees. Butter and flour a 9-inch-square baking pan.
Step 2In a small, deep, heavy stockpot, bring the porter and molasses to a boil over high heat. Carefully whisk in the baking soda (the mixture will bubble up and could easily bubble over the pan if it is not big enough). Remove from heat and set aside until the mixture settles.
Step 3In a large bowl, whisk together the eggs, sugar, brown sugar, apple butter, melted butter and grated ginger. Sift in the flour, baking powder, ground ginger, cinnamon, cloves and nutmeg, then slowly whisk in the beer/molasses mixture. Pour the batter into the prepared pan.
Step 4Bake until the cake is set and a toothpick inserted in the center comes out clean, 55 to 60 minutes. Remove the cake and drizzle over two-thirds cup toffee sauce, then return the cake to the oven and bake for an additional 2 minutes. Remove the cake and cool, still in the pan, on a rack for 30 minutes before serving.
Step 5Serve the warm cake with additional toffee sauce and softly whipped cream.