In a Dutch oven or pot large enough to hold everything, heat the olive oil. Add the onion and bell pepper and sauté for a couple of minutes. Add the garlic and sauté for another 30 seconds. Then add the stock, water, ham hock, cayenne pepper, and black pepper. Bring the pot to a boil, reduce the heat to simmer and cover. Let the mixture cook for 30 minutes.
After 30 minutes, add the black-eyed peas and stir to incorporate. Bring the mixture back to a boil, then reduce again to a simmer. Cook for about an hour and then add the spinach, salt, and hot sauce and stir. Continue to simmer until the peas are tender, about 10-15 more minutes. Taste for doneness – the black-eyed peas should have some texture without being hard and should not be mushy. Check the seasoning and correct if necessary.
Serve with cornbread and extra hot sauce, if desired.