Step 1

Pre heat the oven to 400 degrees F.

Step 2

Add 2 tbsp butter in a pan and add the onions.

Step 3

Cook till onions starts to brown.

Step 4

Add little sprinkling of water and cook till onions are really browned and softened.

Step 5

Add flour and fry for a few seconds.

Step 6

Now add milk very slowly and whisk to make a lump free mixture.

Step 7

Cook the sauce on low heat until it thickens.

Step 8

Add cheddar cheese and cook until it melts.

Step 9

Season with salt and pepper.

Step 10

In a 12 inch cast iron skillet, arrange potato slices in an upright manner.

Step 11

Pour the sauce over the potatoes.

Step 12

Sprinkle the herbs and breadcrumbs on top.

Step 13

Cover the skillet with a foil.

Step 14

Transfer the skillet in the oven and bake for 50-60 minutes until potatoes are tender and slightly browned from the top.

Step 15

Remove the foil and bake for another 10-12 minutes until the potatoes are nicely browned from the top.

Step 16

Remove from oven and serve immediately.