3-6 baby potatoes, boiled, cooled and sliced (see hints below)
1 small - medium onion, thinly chopped
2-3 Tbs olive oil for sauteing onions (plus more as needed)
2 links chorizo sausage, halved lengthwise and cut crosswise into 1/2-inch slices
approx. 5 - 6 ounces baby spinach (or rough chopped larger spinach)
8 large eggs
1/4 cup milk
approx. 1 cup grated cheddar cheese
You'll need a large 10 - 12 inch heavy bottomed oven proof pan or cast iron skillet for this and you'll also need to plan ahead and cook and slice a few small potatoes.
Once the potato is ready to go, start cooking the frittata by adding a splash of olive oil to the large pan on medium heat and sauteing a small to medium size, thinly chopped, onion to soften.
Once the onion is translucent, add two halved and 1/2-inch thick sliced links of chorizo sausage and cook that along for a few minutes.
Then add the sliced, cooked potatoes and cook those along for a minute or two and then add a big handful of baby spinach.
While that's cooking down, crack 8 large eggs into a mixing bowl, add about 1/4 cup of milk to that and whisk it up.
At this point you'll want to turn the oven to the broiler setting because you'll eventually be finishing the frittata underneath the broiler. (see hints below)
Then add a little more olive oil to the skillet and add the beaten eggs and let that cook along for 3 - 4 minutes on medium to medium low heat.
Sprinkle on a generous amount of grated cheddar cheese and place it underneath the broiler.
It's probably a good idea to have the oven rack on the second level down underneath the broiler while you're cooking that and it'll take about 5 - 6 minutes to finish up. (see hints below)
Cook one large diced potato instead of using the smaller baby potatoes.
The broiler part of the procedure can be a little tricky in getting the frittata cooked through without burning the top, so keep your eye on it and adjust the heat and height accordingly, or preheat the oven to 400 degrees and bake it instead.