Preheat to 375F, lightly grease pan with butter or preferred oil
Combine dry ingredients together; combine wet ingredients together then and mix thoroughly until there are no clumps or dry pockets in the cake batter.
Fill muffin sheet 3/4-7/8 full in order allow for rising.
Bake approximately 20 minutes. Slightly less time will be require for mini muffins 15-18 minutes, slightly more for taller cake pan. Adjust times down if using convection oven. The toothpick or knife test is always a great indication (and if you don't mind less than perfect muffin or cake coming out of the oven. Remove from oven once toothpick or knife can be inserted and pulled out dry/clean. For better cooking times, do on separate racks (even with convection oven) as allows for better circulation and quicker heating/rise of all muffins.
Once removed from oven, rest 2 minutes in pan place on rack for cooking prior to plating and/or service.
Notes
Substitute options:Omit CheeseOmit Jalapeno (but why would you?) Sub buttermilk for regular milk and additional butterbutter for oil, but less fluffy