Remove core, membrane and seeds from red bell pepper. Thinly slice.
Peel and slice onion.
In large skillet over medium heat, melt butter, then add oil, red peppers, and onion. Sauté 2 minutes.
Reduce heat to medium-low. Add red wine and basil, cover and continue cooking 15 minutes, stirring occasionally, until onions and peppers soften. Uncover and continue cooking 15 minutes until red wine evaporates.