Preheat the oven to 350°F and use the vegetable shortening to grease a standard 12 cup muffin tin. This recipes makes 16 muffins, so you can use two or make them in batches. Set tin(s) aside.
In a large mixing bowl, whisk the Jiffy mix until large clumps fall apart.
Add the eggs, buttermilk (or cream, cheese, sour cream and jalapeno brine. Mix until just combined. Do not overmix.
Spoon batter into muffin tins, filling 2/3 of each tin. Place a whole jalapeno slice(s) on the top of the batter.
Bake the muffins for 15-17 minutes or until the tops spring back when gently touched and are a puffy, golden yellow.
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