Put a deep pot on low to medium heat, add some butter, olive oil, and one onion, and sauté until caramelized.
Once caramelized, add the peas and continue sautéing for another 1-2 minutes.
Add the cream, lower the heat, season with salt and pepper, cover the pot, and let the it cook for 5 minutes until the peas soften and the cream sets.
Remove from the heat and lightly beat in batches in the mixer. Do not aim for a completely smooth consistency.
Pour into a plate, add the chopped mint leaves, mix with a spoon, and serve.