Cut the squash in half and cook cut side down covered in foil in the oven at 400 degrees (30 - 40 minutes). Scrape the "spaghetti strands" out with a fork and set aside.
Put the butter in a skillet and cook over low heat until the butter starts to brown. Add the capers and the bell peppers and cook until peppers are just tender. Add lemon juice and parsley, then toss sauce with squash.