Melt butter in a large frying pan and add onion; sauté over medium-high heat until translucent. Add garlic and cook until the garlic just starts to turn a light golden colour. Add wine. (It may flare up, but will quickly dissipate. If it doesn’t, simply cover it with a lid to smother the flames.) Once the sizzling stops, add the pesto and blend well. Add the cream and turn the heat to high. Allow the mixture to boil until it starts to turn a beige colour and thickens. Turn off the heat and add cheese. Add cooked penne and toss. Serve with pan-fried salmon that has been seasoned with salt & pepper.