Preheat your oven to 470 F. Line a deep roasting pan with foil and set aside. On a cutting board, cut the cornish hens from its wrappings and pat the skin dry with a paper towel.
With a cleaver or other meat-preparing knife of your choice, cut lengthwise down the center of the chicken. if not already gutted, clean out the innards of your halved hens, then place them side down in the baking pan, leaving plenty of space in between the hens.
Rub the outside of hen each with a 1/2 tablespoon olive oil until fully covered.
In a separate bowl, mix together all of the spices for the spice rub.
Sprinkle the rub on top of the oiled hens and massage into the skin. Lift up the wings and drumstick and sprinkle additional rub for even more flavor. When every halve is rubbed in, place the pan into the oven and roast for 25 minutes.
In a small bowl, mix the sherry with the remaining olive oil.
Take the hens out of the oven after the 25 minute roasting period and lower the heat to 350 F. While the oven is cooling, quickly baste, or spoon the olive oil and sherry mix on top of the hens. At this point, the hens should be a light golden brown and smell slightly fragrant.
When you are done, quickly place in the oven and roast for another 25 minutes. After that, remove the baking pan from the oven and place on a heatproof surface. The skin should be a golden brown and shiny. When pierced with the tip of a knife, the meat should have clear liquid stream out from it. If the clear liquid does not come out, place back in the oven and roast for another 5-10 minutes. Cover with foil until you are ready to serve!
for the mashed potatoes:
Peel and cut your potatoes into 12 chunks and let the pieces soak in cold water for 5 minutes. Strain and set aside.
Boil enough water to cover your potatoes, usually 5-7 cups depending on the size of your potatoes. Once it reaches a boiling point, add the potatoes and boil for 20 minutes.
When you can easily pierce and shake off a piece of potato off a skewer or fork, then they are ready. Strain the potatoes and replace them back in the hot, empty pot. immediately mash your potatoes until small lumps remain.
Add the butter in small chunks and mash until the potatoes become smooth. Fold the potatoes with a spatula to ensure that the butter is completely incorporated.
Add the salt and half-and-half; adjust both salt and half-and-half accordingly to get the taste and texture that you want.
Cover until ready to eat!
To reheat, simply place the pot on a med-low flame and stir to combine and heat evenly.