Clean and trim the leeks and cut into rings. Set some rings aside for garnish, if you like

Cut the bacon into small pieces and place in a skillet.

Add the chopped leeks and fry for about 5 minutes.

Melt the butter in a large saucepan. Add the flour to the butter and stir to combine.

Slowly add the cream and then the vegetable broth while stirring constantly.

Bring the mixture to a boil. Turn the heat down to low and simmer for 10 minutes.

Add the leek and bacon mixture to the hot liquid (reserve some of the bacon for additional garnish if you wish) and simmer for an additional 10 minutes.

Use a hand blender to puree the mixture. Alternatively, transfer the mixture to a food processor or blender to puree and then transfer back to the pot.

Stir in the mustard and season with the salt and freshly ground pepper to taste.

Remove from heat, divide among 4 bowls, garnish and serve.