Step 1

Preheat oven to 350*F

Step 2

Grease a 9 x 13 casserole dish and set aside.

Step 3

Steam carrots until 1/2 way cooked. You want them to be soft enough to bite but still with a bit of a crunch. They'll finish cooking in the oven.

Step 4

As carrots are steaming, in a saucepan combine butter and onion. Cook until onions are soft and translucent.

Step 5

Add flour, salt, mustard and pepper and mix well to create a paste.

Step 6

Slowly add 1/4 cup of milk at a time whisking continually until all the milk has been added to pan. You are making a basic roux. The mixture will thicken quite a bit at first but slowly thin out. If you add all the milk at once you'll have a clumpy mess, so only add 1/4 cup at a time, whisking well.

Step 7

Cook for 5 minutes then turn off burner and add cheese. Mix well until cheese is melted and combined.

Step 8

When carrots are cooked half way, place carrots on the bottom of the casserole dish.

Step 9

Pour cheese mixture on top of carrots ensuring to cover carrots completely.

Step 10

Sprinkle bread crumbs or crushed Ritz crackers on top of sauce and bake for 25 minutes.

Step 11

Remove from oven and serve immediately.