Grilled cheese sandwiches with caramelized onions

Boosting the flavour of a favourite comfort food!

This recipe was inspired by my lifelong love of French onion soup. I use caramelized onions often in various dishes so I tend to cook up about 10 pounds (4.5 kg) of onions at a time then freeze them in half-cup quantities for future use, like in this fantastic pasta dish or these fabulous meatballs. I like Manchego cheese for this sandwich recipe as I find its slightly nutty flavour goes well with the sweet onions but feel free to use your favourite melty cheese such as cheddar, Swiss, mozzarella or even a combination of cheeses. One last tip: I often freeze the bread briefly before assembling grilled cheese sandwiches as I find it makes it much easier to spread the butter. Note that you can use your favourite gluten-free bread to make these sandwiches.

Ingredients

• 2 medium-sized yellow onions
• 1 tablespoon (30 mL) olive oil
• 2 tablespoons butter
• 1/2 teaspoon each kosher salt and black pepper
• pinch of granulated sugar
• 2 tablespoons (30 mL) white wine or water
• 3 oz (85 g) shredded cheese (approx. 1 1/4 cups)
• 4 regular or 6 smaller slices of bread
• 1-2 tablespoons softened butter
• Apple slices and/or pickles, to serve

Method

• Start by caramelizing the onions up to 48 hours in advance (or longer, if you plan to freeze the onions). Peel onions then cut in half and slice thinly. You should have about 2 cups of sliced onions which will reduce to approximately 1/2 cup when caramelized.
• Add olive oil and butter to a medium-sized, heavy duty pan placed over medium heat. When butter has melted, add the sliced onions and stir so they are even coated in butter/oil mixture.
• Cook onions without stirring for 3 minutes then add salt, pepper and sugar. Stir then cover pan and reduce heat to medium-low. Cook for about 35-45 minutes, stirring every 3 or 4 minutes, until onions are beginning to turn golden brown and are getting very soft.
• When onions are uniformly browned, add the wine or water and stir, scraping any stuck bits of onion off the bottom of the pan. When liquid has completely evaporated, remove pan from heat and allow onions to cool to room temperature before assembling sandwiches. (If making onions ahead, transfer to an airtight container and refrigerate or freeze; thaw if frozen, before proceeding.)
• To assemble sandwiches, combine cooled caramelized onions and grated cheese in a small bowl, stirring gently.
• Pair up the bread slices then open them like a book, side by side. Butter the ‘outsides’ of each pair. Flip over one slice of each pair then divide cheese and onion mixture among the flipped slices, spreading to the edges of the bread. Top with remaining bread slices, placed buttered sides up.   
• Cook sandwiches over medium heat in a medium frying pan (I like to use cast iron), pressing down lightly on the bread with a spatula. When the bottom sides are golden, carefully flip the sandwiches and continue to cook until the other side is golden brown and the cheese has melted, keeping a close eye on them to be sure they don’t burn.
• Transfer to serving plates; let rest 2 minutes then cut in half and serve warm with apple slices, pickles or your favourite sandwich accompaniment.

Makes 2-3 sandwiches depending upon size of bread; recipe can easily be multiplied.