Preheat the pressure cooker on sauté.

Add the bacon and brown.

Remove the bacon and set aside for garnishing the soup.

Use a paper towel and tongs to sop up excess grease.

Sauté the onion and deglaze the pan.

Add the celery, potatoes, chicken stock, bay leaf and thyme.

Season with salt and freshly ground black pepper to taste.

Place the lid on and close to locked position.

Turn the steam release valve to closed.

Press the keep warm/cancel button.

Press the manual button and adjust the time to 8 minutes.

In a sauté pan, heat the butter over med/hi.

Whisk in the flour and cook 2 minutes.

Set aside.

When the unit has finished cooking and counted to zero, carefully release the steam.

Press the sauté button.

Add the butter and flour mixture and stir until thickened.

Turn the unit off.

Remove the bay leaf.

Stir in the milk.

Serve with shredded cheddar, chives and bacon as garnish.