You just use your muffin batter & adjust the baking time. More info below. Here is a link that might be useful: Muffin top

Oh! Well, you got the answer for the oil question. It sounds like you had a good result. So, on that theme, I have a few touchpoints. I learned to make cakes out of whatever, when they were the only sweets we had (muffins structurally being cakes). Sometimes, the only fat I had was oil, but I wasn’t using recipes. The rule is if it looks like cake batter, tastes like cake batter, and you didn't forget to put in some baking powder, it's a cake. So with whichever fat, one adjusted as needed. I might put in an extra egg for the water, richness (it was low viscosity cooking oil, not olive) and structure (glue). Muffins, being smaller and weighing less are more tolerant. Early in my time having to do all the Passover cooking by myself, I learned that the kind of fat doesn't matter for the structure in the matzah balls. I think it was Cloudswift who explained that the relative amount of fat was small enough that it just didn't make a difference if it was a couple tablespoons of schmaltz or oil, making vegan easy (though the flavor part requires adjustment). Of course, with dumplings of any kind, the biggest difference is in how they're cooked, whether they become fluffy or leaden or chewy. A group of us were making cookies en masse for a fundraiser, and when we ran out of solid fat, one of the gals subbed oil in a couple of recipes. They ran all over the pans in puddles. If they'd been contained, like in a muffin pan, they might have been okay, but there was nothing to hold them together on sheet pans. Drop cookies are meant to spread and flatten as the fat melts, but with oil, which is already liquid, they just spread and spread. Cut cookies are drier and not supposed to spread, though eggs and/or baking powder will make them puff, which means they get a little bigger sideways, too. They set their shapes pretty quickly, before the fat melts. Oil substitute (there may be recipes developed using oil that work better), while better than in drop cookies, again, spreads too fast for the shapes to set. In enriched breads, for the most part, it's like the matzah balls--too small a percentage to make much difference. I prefer solid vegetable shortening (which I usually hate) or baking sticks (“vegan butter”). Butter in the same proportion is too rich and makes the crumb heavy, and almost greasy-seaming. I'm sure that could be adjusted. I've only used olive oil in pizza crust, but EVOO (in quantity similar to enriched bread, not a spoonful) does give the kind of butteriness you spoke of, without being heavy,. For regular breads, lighter oil works fine, but one uses less. Since the liquid in bread is adjusted by feel, depending on how damp the flour (and air) are, I don't know if there's a specific compensation. Many enriched bread recipes call for oil to begin with. One could check the proportions in a few to make a good estimate of how much to substitute for solid fat. I recently made a recipe that called for oil, where I thought the crumb could be more tender, but I think the recipe was meant to be easy to remember, with no fractions, rather than optimized for the best loaf. I hope some of this is what you were looking for. Happy New Year.

I have had her recipe for a very long time and made them way back when I had my own rhubarb. I don't have rhubarb any more and have not seen any in the stores. I think it is too late in the season here for it. Sue

You can add bran to just about any batter. Bran, as it is, is not really something that has much flavor and it has more value as fiber than it does culinary value. For many, many years I have been making what I call "toasted grains' that we use on cereals and that I use in baking any kind of muffins or breads and also waffle batters. I use 1 part of both sunflower and sesame seeds, 3 parts of wheat germ, and 2 parts of bran. Each of them is sepertely toasted in a hot iron skillet and then mixed in a big bowl and I keep a jar of this in the fridge as a stock item. When toasting each of these in the skillet, the bran is the one that takes a while to toast up. I buy bran at the co op in bulk. It is inexpensive. I love this mix of toasty goodness and will add some into so many things. My go to waffle batter is a combo of whole wheat flour and a generous dose of toasted grains, and molasses and is very much just the same batter as would be a muffin, just baked in a waffle iron instead of an oven. It is the only way I would ever choose to have waffles. Any other waffle I can happily leave behind. I also add it any cooked cereal . it does not have to be cooked, so add it at the end of the cooking. This has been a kitchen staple for many, many years. Yes, it seems that a box of bran based cereal was used because it was more readily available thatn was just real, ordinary bran. It is not expensive, but it can be when purchased in an average grocery store. I buy at the co op. The same with wheat germ. That little jar at the grocery store is way expensive, compared to other sources. My mix would require the entire jar of it!