Heat up a waffle iron, preferably heart-shaped (see notes).
In a large mixing bowl, mix together the melted butter (1 cup), sugar (1.25 cups), and eggs (5) using a whisk or an electric mixer until well combined.
Add the sour cream (8 oz.), water (1/2 cup), milk (1/2 cup), and canola oil (1/2 cup). Mix until well combined.
Mix in the baking powder (1 teaspoon), ground cardamom (4 teaspoons), and vanilla extract (1.5 tablespoons) until well combined.
Add the flour (2 cups) and stir until just combined.
Pour the batter scant 1/2 cup at a time on the hot waffle iron. Cook for one minute, and remove with tongs or a plastic spatula (don't use metal as it may scratch your waffle maker).
Serve hot or at room temperature with gjetost/brunost cheese (Norwegian brown cheese), butter, and lingdonberry or raspberry jam.
I've been very happy with this Euro Cuisine Heart-Shaped Electric Waffle Maker. You can also use a regular waffle maker. This batter is fairly dense so I don't think it would work with a Belgian waffle maker since those a re a lot fluffier. I've also used the batter for pancakes, so if you don't have a waffle maker you can do this in a pinch!
To freeze these waffles, I recommend laying them out on a baking sheet and flash freezing them for about 30 minutes. Then, transfer them to a container or zip-top bag and freeze for up to 2 months for best results (flash freezing will ensure they don't stick together). They defrost quickly in the microwave, but may be too floppy for a standard toaster.