375* oven
Grease your muffin tin with Pam for Baking or Baker's Joy. Set aside.
In a large bowl, combine Flour, Sugar, Baking Powder, Instant Espresso Powder, Salt, and Cinnamon. Give it a whisk to break up any clumps.
In a separate bowl, mix Milk, Butter, Egg, and Vanilla Extract just until blended. I use a larger liquid measuring cup than I need to melt the butter, and I combine all the ingredients in that to save me a bowl.
Make a well in the middle of the dry ingredients (think: volcano shaped) and add the buttery milk mixture. Give it a few swipes with your spoon, but stop before the flour is totally combined. This will ensure you don't overmix your batter since we still have chocolate chips to add and a little flour on the chocolate chips keeps them from sinking into the batter.
NOW add the chocolate chips. Mix until just combined. Once you stop seeing streaks of flour, YOU'RE DONE.
Divide the batter among a dozen muffin cups.
Bake 375* for 15-20 minutes. It takes my oven 17 minutes to bake. How do you know they are done? A toothpick inserted in a non-chocolate chip area will come out clean. The muffin center will spring back lightly when gently pressed. They will look done.
I leave my muffins out, uncovered, with a towel draped over them the first night. After that, if there is an "after that," I store them in a covered, reusable container.