Creamy garlic herb mushroom spaghetti

INGREDIENTS 8 ounces whole wheat pasta (spaghetti, linguine, etc.) – I like DeLallo brand 4 tablespoons butter, divided 3 cloves garlic, minced, divided 16 ounces fresh mushrooms, sliced 2 tablespoons flour (or whole wheat flour) 1 teaspoon herbes de provence 1½ cups milk salt and pepper to taste 3 tablespoons olive oil additional ¼ cup…