Preheat a waffle iron to medium-high.
Whisk the flour with the oats, sugar, wheat germ, baking powder, cinnamon, cardamom and salt in a medium bowl. In another medium bowl, lightly whisk the eggs. To the eggs, add the buttermilk, melted butter, and oil.
Gently stir the wet ingredients into the dry ingredients with a wooden spoon, to make a batter. Take care not to overwork the batter, it's fine if there are a few lumps.
Refrigerate the batter for at least 15 minutes and up to 1 hour. The batter will thicken as it chills, and you want this for even pouring. Do not skip this step.
Remove chilled batter from the refrigerator. Using a 1/3 to 1/2 cup measuring cup (it depends on the size of your waffle iron), pour the batter and cook until the outside of the waffle is crisp and inside is cooked through, about 3 to 5 minutes. The time varies depending on the size and spread of your waffle iron, so consult the appliance instruction booklet if necessary. Repeat with remaining batter.
To serve, consider real maple syrup, salted honey, jam, stewed fruit, or fried chicken and powdered sugar.