Preheat oven to 350 degrees Fahrenheit. Cream butter and sugar with an electric mixer on medium speed for approximately 6 minutes, until fluffy and lighter in color. Scrape the bowl halfway through.
Combine dry ingredients into a medium size bowl and stir with a spoon. Meanwhile spray a 12 hole muffin tin with nonstick spray. Measure out milk and add vinegar.
When butter mixture is done creaming add eggs one at a time until completely combined. Scrape the bowl as necessary.
Add a third of the dry ingredients to the mixer until thoroughly combined, then do the same with a third of the milk mixture. Scrape the bowl as necessary. Continue to do this until all the dry ingredients and milk mixture is incorporated into the batter.
Using a rubber spatula, fold in the semisweet chocolate chips. Using a portion scoop, fill each muffin hole almost all the way full.
Bake at 350 degrees for approximately 22 minutes or until muffins have risen, bounce back to the touch and a toothpick comes out clean. (Poke the muffin more than once to be sure you are not hitting a chocolate chip)