Combine buttermilk, salt, in a large, airtight container. Add chicken pieces, turning to coat in the liquid. Cover, and refrigerate at least 2 hours or overnight.
Combine flour, remaining 1 tsp salt, black pepper, Mrs Dash, Chili powder, and baking powder in a bag. Shake vigorously.One at a time, place chicken pieces in the bag, and shake to coat. Place coated pieces on a clean plate or tray.
Heat vegetable shortening in two 10-inch cast-iron skillets over medium-low heat. Using a frying thermometer to measure temperature, bring shortening to 375 degrees F; it should be at a medium, not a rolling, boil.
Use tongs to place thighs and drumsticks in skillets. Fry until coating is dark golden on bottom, 10 to 14 minutes; then, using tongs, turn chicken over. Cook until coating is dark golden, another 10 to 14 minutes. Drain on brown paper bags or several layered paper towels.