01 -
Put two racks somewhere in the middle of your oven and warm it to 350°F (175°C). Cover two cookie sheets with parchment or silicone mats so nothing sticks and cleanup's a breeze.
02 -
Grab a big bowl and mix the cake mix with baking powder. Give it a good stir. This makes sure the baking powder gets everywhere so your cookies rise right.
03 -
In another smaller bowl, beat together your room-temp eggs, oil, and vanilla until they're all smooth. Room-temp eggs mix way better and make your cookies turn out nicer.
04 -
Dump the egg mixture into your cake mix bowl. Stir everything until you get a soft dough with no dry spots hiding anywhere. Then gently add your tiny chocolate chips, M&Ms, and sprinkles if you're using them. Make sure they're spread out nice and even. Let the dough sit for 10 minutes so it gets easier to handle.
05 -
Scoop about 2 tablespoons of dough for each cookie. Roll them in your hands to make tall oval balls (this helps them stay thick and soft). Put them on your cookie sheets with about 2 inches between them. If you want, stick some extra M&Ms and chips on top to make them look prettier.
06 -
Pop them in the hot oven for 10-11 minutes. They should look set around the edges but still soft in the middle. Don't cook them too long or they'll get crispy. They won't look brown, and that's good. They'll harden up more as they cool down.
07 -
Keep the cookies on the hot sheets for about 3-5 minutes since they'll fall apart if you move them right away. If they look too puffy, you can gently flatten them with the back of a spoon. After they've cooled a bit, move them to a wire rack until they're totally cool. They'll get firmer but still stay soft inside.