For the pork chops: Combine the salt, brown sugar, smoked paprika, cayenne pepper, onion powder and black pepper in a small bowl. Season the pork chops on both sides with the spice mixture, cover with plastic wrap and let sit at room temperature for 1 hour.
For the blue cheese dressing: Meanwhile, whisk the sour cream, milk, mayonnaise, lemon zest and some salt and pepper in a medium bowl until smooth. Fold in the blue cheese so the crumbles do not come apart. Refrigerate the dressing until you serve the salad.
Heat a large cast iron skillet over medium high heat, then add enough olive oil to coat the bottom of the pan; heat. Add the pork chops and cook until golden brown on both sides and a meat thermometer reads 145 degrees F., 6 to 8 minutes per side. Transfer to a plate and let rest 5 minutes.
For the layered salad: Heat a medium cast iron skillet over medium-high heat, add the bacon and cook, turning once, until crispy, 5 to 7 minutes. Drain on a paper towel- lined plate and crumble.
To assemble the salad: Slice the pork chops 1 1/2-inches thick. Put a layer of lettuce in the bottom of the trifle dish, then layer in the spinach, grape tomatoes, onion, hard-boiled eggs, crumbled bacon and peas in that order. Repeat the layers and then top with the pork chops. Serve with the blue cheese dressing.