Making creamy soups in the slow cooker can be tricky because it’s not possible to simmer them with the top off and reduce the liquid. One easy way to thicken without reducing is to use a roux, a mix of flour and butter. Heat the roux in the microwave, then whisk it into the stock in the slow cooker before adding the other ingredients. (If you don’t have a microwave, simply melt the butter in a small saucepan, stir in the flour, let it bubble, then proceed.) This soup is best prepared on the…
