ADD the onion slice, peas, 1/2 teaspoon salt, 1/4 pepper and cook over low heat, stirring occasionally, for about 15 minutes, or until onion is quite transparent with light touches of golden brown.
IN another pan, melt the rest of the butter and add the garlic, pepper flakes, and bay leaves. Set aside, off the heat.Cook the pasta in the boiling water until very al dente; start testing early.
Remove the onion from the first saucepan and discard; add the peas to the pasta.
Reheat the butter mixture until warm and discard the garlic.
Pour the butter mixture over the pasta, mix well, and sprinkle with the oregano.Serve with freshly grated Parmesan.