If you are having a hard time tracking down Muscovado sugar, dark brown sugar is a reasonable substitute.
zest of one lemon
1 1/4 cups / 5 oz / 145 g spelt flour
1 teaspoon baking soda
1/2 teaspoon fine grain sea salt
1 cup / 8 oz / 225g unsalted butter
1 2/3 cups / 7.5 oz / 215 g v. loosely packed dark Muscovado sugar
2 large eggs, beaten
2 teaspoons vanilla extract
4 oz / 115 g bittersweet chocolate, barely melted
1 cup plus 2 tablespoons boiling water
another 1/3 cup / 1.5 oz / 45 g Muscovado sugar (optional)
Preheat oven to 375F / 190C with a rack in the center. Butter a 9x5-inch (23 x 13-cm) loaf pan and line with parchment paper. You have to line the pan if you ever want to get this cake out of it. Sprinkle with the lemon zest and set aside.
Combine the flour baking soda, and salt in a medium bowl. Set aside.
Cream the butter until light and feathery, either with a wooden spoon or with an electric mixer. Beat in the sugar. Then add the eggs, one at a time, scraping down the sides of the bowl a couple times along the way. Add the vanilla, then fold in the melted (and now slightly cooled) chocolate, stirring until just barely combined. Now stir in 1/3 of the flour mixture, then 1/3 of the water, alternating until all the flour and water has been incorporated into what seems like an impossibly thing batter. Go with it. Pour into the prepared pan, place on a rimmed baking sheet (just in case there's an overflow), and bake for 30 minutes. Turn the oven down to 325F / 165C and continue to cook for another 15-18 minutes. The cake isn't going to test done like other cakes, but as long as your oven temp is accurate, you should be fine. Here's an optional step - sprinkle the top of the cake with 1/3 cup of Muscovado sugar and place under a low-broiler for about a minute, or just until the sugar melts.
Place the loaf pan on a rack, let cool completely, and enjoy the next day.
Makes 8 - 10 slices.
I feel so alive tonight
You've got me feeling sublime
I want to yell it from the rooftops down
Until it's over, and we're older
Like sugar and cyanide
Our worlds are meant to collide
I'm gonna yell it from the rooftops down
Till it's over, and we're older