Transfer the paste to a small saucepan. Add the butter and olive oil and bring to a simmer over low heat. Continue simmering for about 5 minutes. Remove the pan from the heat and stir in the lemon zest and lemon juice. Season with salt to taste. Note: This can be made ahead of time and stored in the refrigerator until ready to use. Just be sure to rewarm it slightly before serving — I used the microwave.