Heat your oven to 150°Fan/170°C/325°F/Gas mark 3.
First of all prepare your tin (see "Top Tips" in Notes below). Take your softened butter and "paint" generously into every crevice, nook and cranny in your tin.
Then, take your 4 tablespoons of flour and shake into the inside of the tin, lifting and turning the tin as you go to try to ensure all of the insides are coated.
Then invert your tin onto a baking sheet or similar and tip out the excess flour. Double check every bit of the inside or your tin has been covered and reapply if necessary. This is quite an intricate tin and needs to be liberally coated with butter and sugar to ensure that it comes out in one piece, or you might end up with a ruin rather than a cottage!
Next, gently melt your butter, sugar and golden syrup together over a low heat. Keep squishing the butter to speed things up a bit. Stir regularly with your wooden spoon to ensure everything melts evenly.
Once melted, set aside to cool (if too warm it will scramble your eggs when you add them).
Whilst your mixture cools, add your lemon juice to your milk and mix together, set aside so that it has time to curdle.
Sift your flour, cocoa, baking powder and salt together and set aside.
Once your butter mixture is cool, you can add your eggs. Break in the first one and add a dessertspoonful of your flour mixture. Beat on a low setting until fully incorporated and the lumps of flour have disappeared.
Repeat the above with your second egg.
Then, pour in all of your milk mixture and beat on a low setting, again until just incorporated.
Add in the rest of your flour and beat on a low setting until mixed in.
Then scrape down the side and base of the mixing bowl with your spatula to ensure everything gets mixed together.
Beat on medium-high for about 45 seconds. The mixture will be quite liquidy so don't worry about that.
Pour your cake batter into your tin and place it onto your baking sheet then place into your oven. As the tin is quite large you may need to bake your cake quite low in your oven.
Bake for 1-1¼ hours or until a skewer inserted into the centre of the cake comes out clean.
Leave to cool in the tin for 10-15 minutes then invert it onto a cooling rack to cool.
Once cool decorate with royal icing however you choose!