In a large skillet over medium-low heat, melt the butter and olive oil.
Sauté the garlic and shallots about 2 minutes until tender. Add the sliced carrots, salt and pepper.
Turn the heat to low, cover and cook, stirring occasionally until the carrots are very tender, about 20 minutes. Add a little water if they start to get dry.
Add Marsala and cook, uncovered, until it evaporates, about 3 minutes.