Preheat pressure cooker on sauté.

Pour in the pasta, onion, celery and chicken stock.

Season with salt and freshly ground black pepper.

Place the fresh tuna on top.

Close the lid and turn the steam release valve to closed.

Press keep warm/cancel button.

Press manual and adjust the time to 5 minutes.

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

Stir in the flour and cook 2 minutes.

Remove from heat and set aside.

When the pressure cooker timer has counted to zero, carefully quick release the steam.

Remove the tuna and set aside.

Pour the butter mixture into the pot and press the sauté button.

Stir until thickened.

Turn the unit off.

Stir in the heavy cream.

Stir in the peas and tuna.

Cover with crackers, then cheese.

Place the lid back on with the unit off.

Remove lid after 5 minutes and serve.