Christmas morning is always a blur at our house, and adding a holiday-worthy breakfast into the mix is a bit much. To keep it simple, every year I prep a frittata on the 23rd then just add eggs and bake Christmas morning.

Ruffle Bakeware | Striped Dish Towel | Gold Flatware

Frittata options are endless, and it’s an immensely versatile dish for both the gluten-free and gluten-full crowds alike. This version I’m going for this year is a little different, with the optional addition of smoked salmon if you’re into that sort of thing (which I totally am).

Prep takes about 30 minutes, morning prep is about 5 minutes, bakes for 45-60 minutes – whether it’s Christmas morning, Sunday morning, or a slow day off, this is a great way to get going and make the best of whatever special events are planned.

Print Recipe

4.41 from 5 votes

Caramelized Onion Frittata

This is a great prep-ahead breakfast, perfect for Christmas morning or any other special day where you may want to free up some of your time. Prep up to 48 hours in advance and bake morning of.

Course: Breakfast, Brunch

Ingredients

To caramelize the onions

• 2 sweet onions thinly sliced
• 1 tsp salt
• 2 tbsp olive oil
• 2 tsp balsamic vinegar
• 1 tbsp honey

The rest of the prep

• 2 tbsp olive oil
• 3 cups cremini mushrooms thinly sliced
• 4 handfuls fresh spinach washed
• 2 tbsp garlic minced
• 1 tsp salt
• 1 tsp black pepper
• 2 bags frozen hash browns

Morning-of Ingredients

• 12 eggs
• 1/4 tsp ground nutmeg
• 2 tsp salt
• 1 1/2 tsp black pepper
• 3 oz smoked salmon, skin removed optional

Optional Garnish

• crumbled goat cheese
• fresh dill

Instructions

Caramelize the onions

• In a pan on medium/medium-low, add the olive oil, onions and salt. Cook the onions slowly, allowing them to become soft without burning. Stir frequently.
• Once the onions begin to yellow slightly, add the balsamic and honey. continue cooking, adjusting the temperature to keep a slow cook with no burning in the pan. Once you've achieved a dark golden brown color, remove the onions into a bowl and wipe out the pot. Put it back on medium-high heat.

Finish the prep

• Add the olive oil, mushrooms, salt, and pepper to the pan. Sauté until color begins to develop. Add the garlic, toss together, then add the spinach and gently turn as it cooks and wilts.
• Once the spinach is all wilted, add the mix to the bowl with the caramelized onions. Add the two bags of hash browns and mix together evenly. Taste, add more salt and pepper if needed, then cover and set in the fridge for up to 48 hours.

Morning-of

• Preheat oven to 350. Grease a rectangular casserole dish with bacon fat or olive oil. Whisk the eggs together well in a large bowl. Add the ingredients prepped prior, and mix to combine evenly. Add the nutmeg, salt and pepper, and mix again.
• Pour into greased casserole dish. If using smoked salmon, crumble the salmon over top and gently press down into the mix with a spatula. Cover with foil and bake for 45 minutes.
• Remove foil and broil until all is set and top begins to brown in spots. Allow to cool 10 minutes before cutting into square portions.
• Serve warm, topped with goat cheese (optional) and fresh dill.