Add sliced yellow onions,3 tbsp olive oil, kosher salt, black pepper, paprika, and fresh thyme to an oven safe skillet or cast-iron braiser, toss well. Cover with lid or tightly with foil and roast for one hour stirring halfway through.
Remove caramelized onions from the oven and place in a bowl.
Place the skillet / braiser over a medium high heat add 3 tbsp olive oil and add chicken thighs. Sear the chicken thighs 1 to 2 minutes per side until lightly Golden transfer to a plate.
Reduce to medium heat and add 1 1/2 cups dry orzo. Toast for 1 to 2 minutes, add caramelized onions, chicken stock, and heavy cream. Bring to a gentle simmer until slightly thickened, about 3 minutes.
Nestle the chicken thighs into the orzo mixture cover with lid or tightly wrap in aluminum foil. Bake for 20 to 30 minutes until the chicken is cooked through and the orzo is tender and creamy.