In a large mixing bowl, combine the ground beef (or alternative meat), breadcrumbs, chopped onion, egg, garlic powder, paprika, salt, and pepper. Mix until well combined.

Divide the meat mixture into 12 equal portions. Shape each portion into a small patty, then slightly flatten and round the edges, giving them a slightly bulbous pumpkin-like appearance.

Preheat a grill or frying pan over medium heat. Cook the patties for about 4-5 minutes on each side, or until they are cooked through and reach an internal temperature of 160°F (71°C).

While the patties are cooking, you can prepare the slider buns. If desired, mix orange food coloring into your mayonnaise and lightly coat the buns for a festive touch.

Once the patties are cooked, place one patty on each bun and layer with a slice of cheese, a few lettuce leaves, a slice of tomato, and pickles. Finish with ketchup and mustard on the top bun.

To enhance the pumpkin shape, use a knife to carve small segments on the pulled-up side of each slider, mimicking the look of a pumpkin. You can use a small piece of green bell pepper or spinach for a stem on top.

Arrange the sliders on a platter, and serve them with a side of crispy chips or a fresh salad for a complete meal.