For some reason despite more or less worshipping at the shrine of the spud, I have never made a potato soup without adding either leeks or kale for caldo verde. In fact I’d never heard of cream of potato soup until I moved to England and saw packets of the Erin stuff in Irish sections of the supermarket and discovered it was thought of here as quintessentially Irish.

So when I checked out Ocado’s Irish shop for an event with them and Bord Bia for St Patrick’s Day, I was amused to see that they don’t stock this but lots of things I really do think of as Irish. I decided to make my own cream of potato soup though to be sure and top it with soda bread croutons, fresh dill and smoked salmon to make sure no one confused it with the packet stuff.

Cream of Potato Soup with Soda Bread Croutons (serves 4 to start)

For the soup:

• 1 large onion
• 25g butter
• 500g potatoes
• 650ml vegetable or chicken stock
• 100ml buttermilk
• salt and pepper

For the soda bread:

• 225g plain flour
• 1/2 teaspoon bicarbonate of soda
• 1/2 teaspoon salt
• 1/2 teaspoon sugar
• 250ml buttermilk

To serve:

• 25g fresh dill
• 100g smoked salmon (Irish preferably)

This is a very simple dish with a surprising amount of flavour from very few ingredients. I know I’ve described it as cream of potato but I forgot to buy any so I used the leftover buttermilk instead and the slight tang works brilliantly, so if you use cream, don’t skimp on a squirt of lemon juice too.

Finely slice the onion into half moons and allow it to soften into a sticky caramel tangle in butter over a low heat for about 30 minutes. Or use a batch of my slow cooker caramelised onions from the fridge where they last up to a month.

Peel the potatoes and cut into inch chunks. Add to the pan of onions and pour the stock over it all, seasoning well. Simmer on a low heat until the potatoes are collapsing around the edges for about 25 minutes. Use a handblender to blitz it all into a smooth soup.

It will thick and almost gluey at this stage but don’t panic. Add the buttermilk and blitz again and the texture will lift into a sleek soup with an almost foam like texture to the surface.

While the soup has been cooking, you’ll have been making the soda bread. I do buy mine for a emergency stash in the freezer, but having finally found a source of decent buttermilk, it seemed a shame not to make my own farls here.

Heat a dry heavy bottomed frying pan on the stove. Put the flour in a large bowl and add the sugar, salt and bicarb. Gradually add the buttermilk, bringing the dough together to a lump that shouldn’t be sticky. You may not need all the buttermilk. The acid in it activates the bicarbonate of soda and allows the bread to rise, so if you only milk, don’t forget to sour it with a splash of lemon or vinegar.

Flour the worktop and place the dough on it, pressing it into a circle with your hands until it is about an inch thick. Cut into four pieces or farls and cook two at a time in the dry frying pan giving them about 7 minutes on each side. Flip them over if they start to burn. Repeat with the remaining farls.

To make the croutons, split the farls in half and cut into small cubes. Add some oil or bacon fat to the frying pan and add the cubes to it and fry until the croutons are crisp and golden. Drain on some kitchen roll.

Serve the soup in shallow bowls scattered with the hot croutons, thinly sliced smoked salmon and chopped fresh dill. It probably doesn’t reheat well due to the buttermilk, but as there were only clean bowls from my guests, I’m not sure!