Pre heat oven to about 200C / 400F / Gas 6
In a frying a, heat some oil, over a fairly highheat on the stove
Brown the chicken thighs.
Remove chicken from pan and set aside
Turn down the heat to low, add the onions andgarlic and soften them in the chicken juices. (For around 5 mins)
Empty the pan to sit with the chicken until you'reready to finish the dish
Using the same pan, melt 40g of butter and addthe flour and mustard powder to form a roux (a smooth paste that will cause thegravy to thicken).
Slowly add the stock to the pan, a little at atime, stirring continuously (you don't want lumps) until the sauce is smootherand thicker.
Simmer for 3 mins, then add the herbs.
Put the chicken and onions back with the sauce,into the pan. Slowly add the cream and carefully stir (you don't want the creamto split).
Pour the mixture into an ovenproof dish (the dish used here was 10" X 7.5") and stir in the peas.
Peel and thinly slice the potatoes, (approx 5 mm)
Arrange the slices over the chicken mixtureoverlapping so the surface is completely covered
Heat the remaining butter to just melted andbrush over the potatoes
Bake the potatoes in the oven for 35 mins untilthey are golden brown and crispy