Sprinkle the pheasant with salt and let it sit for about 30 minutes
Rinse the apples but do not peel them. Core and slice the apples into wedges (around 1/2” thick).
Over medium heat, melt 2 Tbsp butter in a dutch oven or thick walled pot. Place the apples in the heated butter in a single layer (may have to do 2 separate batches). Gently brown the apples for a few minutes and then turn them over and brown on the other side. Remove fried apples to a plate and cook the second batch. Remove the second batch of apples and reserve all of them until later.
Add another 2 Tbsp butter to the pot and melt over med-high heat. Dust the pheasant pieces lightly in flour on both sides and lay in the pot in a single layer. Make sure the pheasant is not crowded. Brown lightly on both sides for a few minutes. Use less browning time if you are using breast meat as it will dry out quicker. Remove pheasant to a plate and reserve.
Increase the heat a bit and add the sliced onions. Add more butter if necessary to carmelize the onions. Cook the onions for about 5 minutes or until carmelized, stirring occasionally.
Turn off the heat and pour in the apple brandy to deglaze the pot. It will steam up and release all the brown bits on the bottom of the pot. Let the brandy boil down until reduced by half. Then add the cider and bring to a boil.
Strip the thyme leaves from the stems (or use dried thyme) and add to the pot. Place the reserved phesant pices back in the pot, cover and simmer until pheasant is tender. This may take 1 1/2 to 2 1/2 hours depending on your pheasant and your tastes. Prick with a fork to see if it is tender enough.
Remove the pheasant from the pot and set aside. Turn the heat to high and add back in the apples and boil down to your preferred consistency. This can be soupy to syrupy, depending on your tastes. When it is to the consistency you like, turn off the heat and add the dijon mustard and the cream and salt. Mix all together thoroughly and serve
Serve by spooning the cider-apple sauce into the serving dish and laying the pheasant and fresh thyme on top.