Step 1

Heat the oven to 350 F. Grease an 8- by 8-inch baking pan.

Step 2

Combine the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment and cream on high until homogenous, about 3 minutes. Add the eggs, oil and vanilla, and mix until just combined, about 1 minute.

Step 3

Add the flour, salt and baking soda, mixing until just combined, about 30 seconds. Mix in the milk until just combined, about 30 seconds.

Step 4

Spread the dough in an even layer in the prepared pan. Add sprinkles of choice on top of cookie dough, or mix together 1 tablespoon sugar and 1 teaspoon ground cinnamon in a small bowl and sprinkle evenly over the dough.

Step 5

Bake for 20 to 25 minutes for a slightly under-baked cookie (which is how I like it), or for another 3 to 5 minutes if you're a firm cookie fan. Cool completely in the pan before cutting into squares.