Sarah's Lemon Pasta / Les Pâtes au Citron de Sarah

Ok so the name is a misnomer because the original recipe comes from somewhere else. But the first time I made it was with my friend Sarah so now I think of it as her pasta recipe.

Ingredients
Spaghetti
3-5 cloves garlic, minced
1 Meyer lemon (organic preferred because you'll be using the rind)
Butter
1 shallot or onion, chopped
1 tbsp sugar
Pinch of salt
1/3 c breadcrumbs
1 bunch parsley, chopped
Parmesan, grated
Red pepper flakes, to taste
Salt and pepper, to taste

Directions
1) Zest the lemon so you get 2 tsp of zest, then de-seed and chop up your lemon into thin slices.
2) Put the sugar, salt, and lemon in a small bowl, toss it to combine it, and let it sit to marinate.
3) Toast the breadcrumbs with one clove of the garlic and some salt and pepper.
4) Put the lemon, rest of the garlic, shallot, and red pepper flakes in a pan and cook on low until the shallot has softened.
5) Make the pasta and save about 3/4 c of the pasta water for later.
6) Put the butter, lemon zest, pasta, and 1/2 c of the pasta water in the pan with everything else. Cook it on medium high for a couple minutes until the butter has melted. Stir it up so the pasta is coated with the other ingredients. If your pasta seems dry you can add in the rest of the pasta water.
7) Serve the pasta sprinkled with the toasted breadcrumbs, parmesan, and parsley.