Friday, 18 January 2013
It's been snowing all day in Oxford. I spent most of the day in the kitchen, watching the flakes fall and gather outside.
I've made this pound cake four times in two weeks. It's simple but shockingly good. Brown butter usually ends up as a background to other flavours, which is a shame (though I'm guilty of using it in all sorts of recipes). This cake keeps really well in a tin and freezes beautifully, as well as being both robust and fluffy.
When I first set about converting this cake from the original olive oil version to butter, I realised I had no way of working out how much solid butter I needed to create the required volume of liquid brown butter. Guessing seemed a bit... boring. Guessing also wouldn't help me the next time I needed to do it. So I spent my Sunday afternoon browning most of the butter in our fridge, armed with a calculator and the scales.
On the butter packet it should tell you the % of fat, protein and so on. The fat is usually around 82% (I believe it has to be 80% to be classed as butter) and the others total about 1%. This is what will be left when you've browned the butter and the water has evaporated - so for 100g of solid butter you'll get 83g of brown butter.
After experimenting, I worked out that the density of brown butter is 0.93 g/ml (mass/volume, 93g of brown butter is 100ml).
To work out how much solid butter you'll need, you first calculate the weight of brown butter you'll need to get the correct volume by rearranging the density formula (this recipe is the example in bold):
required volume (165, ml) x 0.93 (density) = mass of brown butter (153, g)
Then work out the amount of solid butter needed to create that mass of brown butter, using the package percentages:
mass of brown butter (153, g) / 0.83 (% of fat + others in butter) = mass of solid butter (185g, rounded up to nearest workable weight from 184.3)
I've tried it out a few times and it's always worked. So, erm... yes. For those of you who want to try swapping brown butter for oils in recipes, no need to guess.
[/baking geekery] (Does it make it worse that I just spent a good ten minutes looking up the etymology of 'geek', 'nerd', 'boffin' etc on the OED? Probably.)
Brown Butter Pound Cake
(adapted from Cardamon Orange Pound Cake, which was adapted from the Olive Oil Pound Cake in Alice Medrich's Sinfully Easy Delicious Desserts)
185g unsalted butter
200g caster sugar
pinch of fine sea salt
3 eggs, cold from the fridge
200g plain flour
1 and 1/4 tsp baking powder
165ml whole milk
1 tsp vanilla paste (or extract)
Place the butter into a big pan and set over medium heat. Keep heating until you have brown butter (see this post for more detail/a step-by-step). Pour into a bowl and leave to cool - it needs to be room temperature. If there's any foam still lingering, spoon it off.
Preheat the oven to 180C/350F. Either line a loaf tin (around 9"/23cm long) or carefully grease a round/decorated tin (the one shown is about 8.5"/21cm across). Scrape the cooled butter into a stand mixer bowl and add the sugar and salt. Beat together until creamy, then add the eggs one by one, beating in between. If it curdles, don't worry - that's normal. Beat on medium-high for 5 minutes (do time this, it makes a difference) until pale and thick.
Sieve the flour and baking powder together. Tip a third into the mix and stir together on low. Slowly add half of the milk and briefly beat. Add another 1/3 of the flour, the rest of the milk, then the rest of the flour, combining in between. Add the vanilla and beat together one last time. Scoop into the tin and spread out.
Bake for 45-50 minutes until a toothpick comes out clean and the cake is a deep brown. Leave to cool in the tin for 5 minutes then turn out onto a rack. Best eaten once cooled. Keeps well in a tin for a few days and freezes extremely well.
(Makes one cake, about 16 slices)
A few related posts:
Old Fashioned Sponge Cake
Ginger Root Bundt Cake
Cardamon Orange Pound Cake