Cut the turkey into bite-sized chunks or stripes.
Finely chop the onion and bell pepper.
Heat a little oil in a heavy-based pan, then gently sauté the onion and bell pepper for about 5 minutes. When softened, add the turkey and thyme leaves. Season with salt and pepper and stir until the meat has changed colour.
Add the mushrooms and a drop water or lemon juice. Put a lid on and sauté for about 10 minutes until the mushrooms have released their liquid.
Add the bay leaf, mustard and cream.
Cook for about 5 minutes, stirring, until you a get a thick, silky sauce.
Taste and adjust the seasoning to your liking - you might want to add a drop of lemon juice to it.
Discard the bay leaf and serve warm.