In a 8 to 10-inch nonstick saute pan, melt the butter over medium heat until just turning brown. Add the egg mixture and cook slowly for 12 to 15 minutes, until set on bottom. Carefully flip over and continue cooking 6 to 7 minutes, until set.
Once the frittata is done, allow to cool for 10 minutes. After the frittata has cooled, combine the remaining herbs in a medium-sized bowl. Add the vinegar, olive oil, salt, and pepper, and toss well. Taste the salad and adjust the seasonings, if necessary. Serve the frittata cut into wedges, alongside the dressed herb salad.