Help! I've just followed the recipe from Cupcake Jemma's cookbook (which I noticed is slightly different than the recipe in her yt video) for the double chocolate chip ny style cookie. It did not spread at all and came out just like a baseball. What's going on?? Some details that might be helpful to know: I live at sea level. I mixed the dough by hand. I froze the dough balls for 2 hours. Never used a thermometer for my oven so maybe it's a bit off. I used a couple 'american' substitutions which I'll point out in the ingredients list.

Here's the ingredients:

• 230g cold butter
• 160g soft brown sugar
• 160g white sugar (substituted for casters sugar)
• 400g dark chocolate chips
• 300g plain flour
• 130g self raising flour (this was homemade, I added about 1.75 tsp baking powder to AP flour)
• 70g cocoa
• 1 tsp salt
• 2 tsp baking powder
• 2 eggs plus one egg yolk

I baked 2 cookies on a dark baking sheet for 16 minutes at 410f (the oven was preheated, the baking sheet wasn't)

Any ideas why these didn't spread like they are supposed to? I thought the dough looked pretty good and was also careful not to roll them, just barely squeezing them into balls. Any insight would be greatly appreciated! :)

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