The Service Cookbook (Mrs. Ida Bailey Allen, 1933) represents the '30s with Braised Calves' Hearts with Carrots:
The recipe is not much of a surprise once you've read the title: calves' hearts, carrots, and in the closest thing we get to a shocking turn: onions! You'll notice the long cooking time, common to all of today's recipes, because hearts are tough. (Way tougher than human hearts, which break pretty easily judging from country music. They're also pretty easy to literally break, too, judging from movies like Indiana Jones and the Temple of Doom.)
For the '40s, we have The American Woman's Cook Book (Ed. Ruth Berolzheimer, 1942) with Sweet-Sour Hearts:
Now if we say we got someone sweet and sour hearts for Valentine's day, that usually means a specialty variation of those chalky conversation hearts, but in the '40s it meant actual veal hearts cooked in vinegar, sugar, and onion. (I'm not quite sure which of those options would be worse...)
Things get very organ-y in the '50s, with Picture Cook Book (Time Incorporated, 1958):
Veal Heart and Red Wine Stew also boasts veal kidneys and pork liver, along with the wine, celery, parsley, and mushrooms. The wine probably makes this the most Valentine-appropriate of the bunch, but I personally would not want to spend the holiday dicing organ meats.
The Better Homes and Gardens New Cook Book (1965) is much more economical:
Chicken-Fried Heart looks more like it is braised than chicken-fried to me. This recipe does start with frying the meat that has been dredged in flour, but the step after that for chicken-fried steak is to eat it. Here, the heart is cooked in hot water for two hours after the frying, so I doubt it tastes particularly chicken fried by the time it's done. Maybe it tastes kind of like someone briefly thought about chicken-frying it and then realized that was a bad idea?
My last heart for you is from The Wise Encyclopedia of Cookery (1971):
Beef Heart with Rice Stuffing fills the heart with rice, onions, raisins(!), egg, and seasonings, then sews it up and simmers it in seasoned water with tomatoes. While I love recipes that double as craft projects, I'm not sure an afternoon sewing up a heart would be my idea of fun....
So there you have it-- fifty years of heart recipes, whether you wanted them or not! Happy Valentine's Day from the worst gift-giver ever. ;-)