First preheat your oven to 350° F (175° C).

To prepare your mise en place, first cut the bottom white part from the leek. Cut in half lengthwise and wash thoroughly. Cut each half lengthwise into about 3 or 4 long strips and then dice. Slice the ham into medium dice and grate the cheese. Place the eggs into a bowl, measure out the cream and set aside.

Heat a 10" -inch non-stick, oven-proof pan over medium-low heat.

Place the oil in the pan and sweat the leeks until softened, about 5 minutes or so. While the leeks are sweating, you can begin to assemble the ingredients.

To assemble the frittata, first whisk the eggs. Season with salt and pepper. Add the cream and whisk everything together. Next, add the cheese, ham, and cooked leeks. Stir to evenly combine.

With the pan over medium-low heat, swirl the oil around the pan. Once warm, pour the egg mixture into the pan.

Using a heat-proof rubber spatula, gently agitate the eggs. Move the ingredients from the outside of the pan towards the center, while scraping the bottom of the pan. Scrape around the side of the pan too. Slowly cook the frittata until it is cooked about half way through. There should be cooked egg scattered throughout with wet (not runny) egg in between. Just before transferring the frittata to the oven, flatten out the surface, if necessary. Give the pan one last sweep around the edge to tidy it up.

Transfer the frittata to the upper third rack of the oven and bake until the center just sets, about 5 to 10 minutes. Once done, remove from the oven and let cool in the pan for a few minutes until the steam subsides. Slide the frittata out of the pan onto a cutting board or serving tray. Slice and serve.