While substituting cream for milk in a custard just gives you a richer custard, for a cake usually you'd thin the cream with water. The amount of water matters in cake. When cream rises to the top of the milk (unhomogenized) it's floating on the water. Stir it back in and you get whole milk. I think it's supposed to be equal parts cream and milk by volume, but look that up.

Heat is what usually makes sugar melt. When you make a traditional cake, you cream the butter with the sugar to get a stable aeration, and the sugar gets smashed, and can dissolve some from the water content of the butter. When you add the milk (which has a lot of water) or water, it can dissolve further, but it really melts in the oven and acts like a liquid.

Oil cakes have different ratios than butter cakes, partly because while oil is liquid, it doesn't have any water content. I can't tell you if this is what made your cake oily, however. It could be the cream, but I don't know enough to be completely sure.

You might try using a finer sugar next time.... Bakers' Sugar/Bar Sugar. I use to have it for cold drinks because it dissolves better, but found that in baking, etc. it actually works better than regular sugar.

Cream is pretty well all fat, so I don't think that helped your oil problem. The proportion of cream in whole milk is quite small, as whole milk is only 4% fat. We used to get unhomogenised milk in bottles when I was young, and a British pint (20fl oz) bottle had the cream floating at the top. It only filled the sloped section at the top of the bottle, so it was probably 1 fl oz or less.

That seems like a lot of oil for that size mug - I checked a couple of other recipes and they call for only 2 TBL. I would reduce the oil a bit more than 2 TBL if using cream, but also would mix it up a few minutes before baking to let the sugar dissolve a bit, then stir and bake.

Kate has a good point about the sugar crystals. A standard cake is fine with basic granulated cane sugar, but some trickier ones are much better with superfine (caster) sugar. You can just run your sugar through the food processor, though doing that can etch the bowl.

I don’t know that there will be a “next time.” I will make a note to reduce the oil, should there be. A “mug cake” is supposed to be quick and easy. I won’t be dragging out the FP to make the sugar superfine. It was good cold this morning, but the Chocolate chips were a tad crunchy. It really needs vanilla ice cream!

I have burned the middle finger on my left hand. It is making typing difficult. I immediately stuck it in ice water. That has helped, but it is going to be a blister nevertheless.

I have made this, and although tasty it is very messy. Believe a larger cup in the micro is necessary. Mine spilled/boiled over and made a mess. But IT WAS GOOD.

Next time I will make it in my pyrex 4 cup measuring cup.

bbstx so sorry about your finger. Ouch. Hope it doesn't blister too badly and heals quickly.

This sounded good to me so I made it as written...mostly. I never have whole milk so I used our usual fat free milk. We had mini chocolate chips so that is what I used. And I cleaned up the excess on the sides with my finger instead of a paper towel and sampled that raw. It was cooked 90 seconds in a 1000 W microwave and cooled 2 minutes.

My DH and I thought it was great. No sugar grains, no oozing oil. Just yummy very chocolaty cake-like goodness that begged for some vanilla ice cream that we do not have. Freezer space is needed for other items right now - like freezing quart portions of milk when we are able to buy a gallon.

I'll be making this again and making sure DH knows how to make it, too. He is the big cake lover here.

So, I would say your cream affected the outcome a lot. Try it again when the listed ingredients aren't so hard to come by and then go exercise to help the waistline. I might cut back on the cocoa by 1 T since the chocolate taste was really strong and yummy - but doable with less if the cocoa powder supply is limited like mine is right now.

@bragu_DSM 5, try putting your mug off-center in the microwave. When I was on a beyond-ridiculous diet, I ate a “muffin” every morning. It came with its own bowl. At my house it cooked fine. At my sister’s, it boiled over. I have a free-standing MW with turntable; she has a drawer MW without turntable. When I went the next time, DBIL said someone had told him to cook off center if your MW doesn’t have a turntable. I did and there was no problem with a boil over. I have no idea how or why it works, but it does.

@ediej1209 AL Zn 7, apparently plunging my finger immediately into my glass of ice water saved the day. Last night, it hurt a bit. But this morning, the tip end that I burned feels strange, but so far there is no blister!

@naturegirl_2007 5B SW Michigan, I’m so glad to hear that you had success making the mug cake! I think I’ll give it a try again, but it will be a while. I cannot indulge often. On another thread someone mentioned that instead of the Freshman 15, we were all going to be gaining the COVID 19! HA!

I was going to add a tad of whipped cream on top, but the Zoom party was starting and I didn’t have time. I can make soft whipped cream with my aerator gizmo. I have this one.

"That seems like a lot of oil for that size mug - I checked a couple of other recipes and they call for only 2 TBL."

I thought the same thing after checking several recipes. Each one called for 2 T.

Oh, I'm so happy--ridiculously happy--about your finger. Day brightener!

I agree that the cream would be the cause of failure, since it's mainly fat and would not dissolve sugar very well. Have you ever tried dissolving sugar into straight cream that wasn't heated?

bbstx, Happy to hear about your finger. Yay for no blister!!

I wanted to try this but realized I didn't have any chocolate chips. I wasn’t sure how it would turn out without the chips. So, I looked online for a recipe that didn’t require chocolate chips and made it for my husband.

I didn’t want to make two just in case it was a bust. He really liked it and saved two spoonfuls for me. I thought it was good too. Instead of chocolate chips mixed throughout the batter, it called for a blob of Nutella or peanut butter or Biscoff Cookie Butter plopped in the center. I used peanut butter and reconstituted whole milk powder.

I only cooked mine for 65 seconds since my microwave has more wattage than the blog writer’s. I got distracted and didn’t get around to serving it to my husband for about 10 minutes. So, it wasn’t hot. But it was still moist, and the peanut butter was still a bit warm.

All in all, I was really quite pleased. It went together quickly and was a tasty treat. My husband thought it was a cross between a chocolate cake and a brownie. The blog writer has other mug cake recipes that I might try too. I like the fact that it was quick, easy, and made a single serving.

Thanks BBSTX for reporting on your experiment.

https://www.tablefortwoblog.com/the-moistest-chocolate-mug-cake/

@shambo, the Pioneer Woman recipe itself doesn’t say so, but a caption under one of the photographs in the blog post refers to the chocolate chips as “optional.” You might need to make a PW mug cake to compare - strictly for scientific purposes, of course.

Oh, you are correct. Yes, one mustn't ignore the need for scientific exploration. My husband asked for the mug cake again for dessert tonight. So, no matter which recipe I use, I think I've created a monster. Ha!

Actually, I'm really happy about the results. I especially like not having a huge "sweet thing" hanging around the house. I know I can freeze slices of cake or brownies or cookies, but I freeze all sorts of breakfast items. Sometimes I am just plain ornery and don't want to portion and freeze any more stuff.

There are a ton of recipes for 6" cakes. They're real cakes from real cake pans but petite. :) Of course, if you make four layers, it's just a tall skinny 9" cake. :)

Bbstx, there's also mind over matter. I once touched the tip of my soldering iron when it was nowhere near cool. I was on a looming deadline and in no state to find ice, I was totally emotionally invested (I was young) in not having to deal with a burn and I just kept working. No mark, no blister, no red, barely any sting left, no nothin'.

YIKES! My mind isn’t that strong!

I thought the PW mug cake was a little large. DH ate all of his. I only ate half of mine the night I made it. I ate the other half the next morning for breakfast! I love chocolate for breakfast!

I have eaten a mug cake several times but never made one.....no issues...no grainy...no spill over....just a little bitty chocolate cake.
Try another recipe.
And don't over think....yeah cream wasn't a good idea but shouldn't have made such a disaster.....I suspect it was a bad recipe.