You can stuff and roast a heart very nicely, with mixed breadcrumb stuffing. First, take out some of the tough sinews from the heart cavity. I save the crusts from all bread, grate and store in a jar in the freezer not to pick up freezer odours. Then for a stuffing add butter, savoury salt and pepper to taste, pack in as much stuffing as you can get in, keep closed with a skewer or sew it shut (no fancy stitches needed here!) and roast at a slightly slower temp than a regular roast of beef. Heart is 'close' meat as my grandfather used to say and can get tough if roasted at too high a heat. A little broth or water in the roasting pan helps too
Another thing you can do with heart is use it as ground meat - again take out the tough bits then grind in a food processor or old fashioned meat grinder (don't know if you can get them any more, maybe in a thrift shop! Adele Davis a health food author of the last century used to call this recipe half-hearted hamburgers. My kids liked them as much as any other meat patties.
All the boiling, simmering and stewing recipes listed here would be great. Pot roast with lots of onion carrots, turnip and potatoes is great.
Heart is a great source of protein, delicious and relatively inexpensive, valued in many cultures. Congrats to you and your boyfriend for being open to new foods, I'm usre you will find this one a real taste treat.

I never had it but my mom said my grandmother would stuff it with a dressing or stuffing & bake in oven. That is all I remember.

While living the farm life, we always butchered and the way i always made it...my favorite...was ro make stuffing as for a chicken etc, and stuff the heart....bake it at 325 for 3-4 hours covered..I use a blue roaster...you can either add a bit of water or dry cook, your preference...now am hungary for one!!! May have to go to butcher shop this week! :D

SLICE IT UP AND CUBE IT ROLL IT IN FLOUR AND FRY IT

IT IS GOOD THAT WAY TASTED LIKE STAKE

Used to pickle it for my ex...just boiled it til done, then sliced it into a regular pickle brine...(you can get a recipe anywhere for that)

I usually boil w/vegies like most have already posted. Very tasty IMO

Put it in a pot with water, seasoning, and horseradish, cook until done. Or, I have made dressing and put it down in the dressing and baked it.

My kids claimed they didn't like heart so I use to grind it up. Remove the tough parts , grind it and put it in homemade pasta sauce. Gives it a very strong beefy flavor.

I remember my mom stuffing it with a bread stuffing and roasting it. It actually tasted pretty good and us kids all knew what we were eating and still enjoyed it. We lived on a farm, so none of us were picky eaters. Give it a try and good luck, you may enjoy it.