Heat oven to 400°F. Arrange speck or prosciutto in a single layer on parchment-lined baking sheets and roast 10 minutes or until crispy. Cool and reserve.
Heat a cast-iron skillet over medium-high heat.
Juice one of the oranges and slice the other, discarding ends. Crack and chop 2 large cloves garlic. Strip 2-3 stems of rosemary and chop.
Season chicken with salt and pepper on both sides and lightly dredge in flour.
Add oil to pan, 4 turns. Cook chicken about 4 minutes on each side to golden and remove to plate. Add orange slices and caramelize on each side, 1 minute. Top the chicken with the orange slices.
Add another drizzle of oil to the pan along with the chopped garlic and rosemary. Stir 30 seconds then add orange juice and deglaze pan. Add 2 tablespoons vinegar, stir and add about 3/4 cup of stock. Add the chicken and sliced oranges back to the skillet; turn to coat. Simmer 2 minutes.
Top chicken in the pan with crispy broken pieces of speck or prosciutto and serve right out of the skillet.
* Normally I count vinegar as a “buy” ingredient but this recipe can use any vinegar so I count it as pantry – we all have at least one type of vinegar in the cupboard.