Totally Chocolate Chocolate Chip Cookies

Our answer

Unfortunately switching dark (bittersweet) and white chocolate in cake and cookie batters can cause problems as the two chocolates are actually very different. White chocolate only contains cocoa fat, sugar and vanilla and no cocoa solids so will have a much higher fat content than dark chocolate. Also cocoa tends to absorb a lot more liquid and fat than flour does so the cookie batter with white chocolate will end up with an overall higher fat content and slightly softer batter and these factors will be causing the cookies to spread. We would suggest only switching the chocolate chips from dark to white and as white chocolate chips can burn a little more easily than dark ones it is worth checking the cookies a couple of minutes early to make sure that the chocolate chips on the bottom of the cookies aren't turning too dark.

If your cookies using the original recipe are spreading then it is most likely that the dough has become a little too warm. Shape the cookies on the baking sheet and chill for 20-30 minutes until cold and then bake them (you can preheat the oven while the cookies chill). It could also be that your oven is running slightly cold so the outside of the cookie does not set quickly enough and they spread. If you have an oven thermometer then just check the oven temperature by putting it in the oven while it preheats or you could try preheating the oven to 180c (350F) then turning it down to 170c (325F) once the cookies have gone into the oven. If the cookies are still spreading too much then you may need to add a little bit more plain (all-purpose) flour to the dough (flours do vary) or reduce the bicarbonate of soda (baking soda) slightly.