I woke up to frost on the ground this morning, while I’m still wishing for Spring. Maybe that is why it felt colder than the deep winter of a few months ago.  This frost, and the cold wind and rain we’ve been having started me thinking about foods that warm you.

Soup!

Two Old Men Eating Soup, 1819–23, by Francisco de Goya, currently in the Museo del Prado, Madrid, Spain

Soup is a very old dish. It is as old as fire and a container to boil water in. The oldest written egg soup recipe I could find was from the early 16^th century in England. The recipe is simple: For each person, take strong-flavored broth; one beaten egg; an egg-size chunk of cheese, cut into small bits; minced scallion or green onion; and minced spring greens. Take boiling stock, skim off any foam, beat egg and whisk it into the broth, and add cheese and greens before serving.

There are a great many recipes that add a few eggs to hot soup to be poached or stirred in to create a creamier, more nutritious soup. Other recipes call for an egg to be added to a small amount of broth and beaten before it is added to the rest of the soup (tempering the egg—diluting it with some of the liquid—makes it less likely to curdle when added to a full pot of broth). There are a few recipes for a custard-based soup, although the real problem with eggs in soups is that they “break” easily (and become granular) with heat that is prolonged or too high.

The most numerous egg-in-soup recipes—for egg drop soup—make the most of an egg cooking in hot liquid. They involve stirring an untempered beaten raw egg into hot soup to create ribbons of cooked egg. In other recipes, this would be called curdling, but it is a desirable attribute in this case. Egg drop soups include the famous Chinese egg drop soup as well as the Central American sopa de anjo (garlic soup) and Greek avgolemono (egg-and-lemon chicken soup).

Syllabub and German Biersuppe are not quite dessert and not savory. They’re more like soup than like egg drinks but are still borderline. Biersuppe and syllabub are both very old versions of liquid nutrition, or early instant breakfast. They share a history with eggnog and other alcohol-and-egg drinks. They are interesting in that the recipes have persisted to modern times, although often not as breakfast or quick lunch meals but, rather, as appetizers, palate cleansers, or offbeat desserts.

And, finally, there is a dessert type of egg soup. These sweet soups are often served for either breakfast or dessert. Some are warm; others are cold. Included are buttermilk soups (usually cold) and a dessert that was popular prior to World War II, Œufs à la neige (also known as floating islands, clouds, and snow eggs). My grandmother was especially fond of her floating islands, firm blobs of meringue poached in a custard and then served floating in a ladleful of the custard. (It is a dessert I had long forgotten about until I tried the recipe.)

Any soup can have a poached egg added to it, and many people do this routinely. The egg is usually poached in the soup, but some people poach the egg in simmering water and then slide it into the soup before serving. The situation in which to poach an egg separately is when your soup is opaque. (It is a little disconcerting when you drop a few eggs into the soup and cannot find them to serve. They drop to the bottom of the pot and are very elusive.) It is another reason some recipes say to put a raw egg in a bowl and then ladle soup over it. This is fine for those who like their poached eggs on the very runny side, as the temperature in the soup bowl quickly drops and the egg doesn’t cook very much. The egg adds extra nutrition to the soup and, with clear soups, visual interest. One very popular poached egg soup is “eggs in purgatory,” which sounds quite daring and slightly naughty. It is eggs poached in tomato soup. A similar recipe is Israel’s shakshuka, which is spicier.

Eggs in Purgatory Soup

• 3 cups diced tomatoes
• ¼ cup olive oil
• ½ cup chopped onion
• 2 tablespoons flour
• 1 teaspoon cornstarch
• 1 teaspoon Worcestershire sauce
• ½ teaspoon honey
• ½ teaspoon balsamic vinegar
• salt and pepper, to taste
• 1 cup cream
• 1 cup milk
• 1 egg per serving

In blender or food processor, blend tomatoes until liquid. Set aside. In large cooking pot, heat olive oil to very hot. Add onions, and sauté until lightly browned. Turn heat down, and add flour and cornstarch to make smooth roux. Add pureed tomatoes. Stir until blended, and heat until boiling. Add Worcestershire sauce, honey, balsamic vinegar, and salt and pepper. Reduce heat to simmer, and let soup simmer 20 minutes. Remove from heat, and, while stirring constantly, add cream. Then add milk. Continue to stir, and return pot to stove on low heat. Stir constantly 10 minutes, to let soup heat thoroughly. Remove from heat. Poach one egg for each serving. Crack eggs into measuring cup, and slowly pour into soup. With slotted spoon, move eggs apart and roll them occasionally while cooking (4 to 6 minutes). Ladle soup and poached egg into individual serving bowls.

Shakshuka (Israel)

• ¼ cup olive oil
  3 jalapeño peppers, seeded and chopped
  1 cup chopped onion
• 5 cloves garlic, crushed and minced
  1 teaspoon ground cumin
• 1 tablespoon smoked paprika
• 3 cups diced tomatoes
• ½ cup red wine
  6 eggs
  ½ cup crumbled feta cheese for garnish
  chopped cilantro or Italian parsley for garnish
  warm pitas for serving

In deep-sided skillet, heat olive oil until very hot. Sauté chilies and onions together until limp. Add garlic, cumin, and paprika, and cook several more minutes until garlic is soft. Add diced tomatoes and red wine. Cook on medium heat, stirring occasionally, until flavors are blended and soup is boiling. Turn off heat, and slide whole eggs into soup, distributed across surface. Cover skillet 5 minutes to let eggs set. Remove poached eggs with slotted spoon, and put into individual serving dishes. Ladle hot soup over eggs, and garnish with feta and cilantro. Serve with pita bread.