Rhubarb muffins with sour cream and streusel

This easy recipe for rhubarb muffins with sour cream is topped with a streusel topping before baking, yielding a moist muffin with a crunchy crumble topping. You can use fresh or frozen rhubarb for this rhubarb streusel muffin recipe.

Making muffins less tough—the type of flour

To bake cakes and muffins that are more tender, one easy option to consider would be to use cake flour instead of all-purpose flour:

• Cake flour is a finer flour, coming from a finer-milled soft variety of wheat, so it has a lower protein content, more starch, and a finer, softer texture. This leads to softer, more tender baked goods
• All-purpose flour has a high protein content and some brands of all-purpose may come from a blend of a couple wheat varieties, both hard and soft, which give it it's "all-purpose" properties

A common baking substitution for cake flour is to replace it with all-purpose mixed with cornstarch. This is another way of reducing the protein content slightly and adding a little more starch to cake batters.

Knowing this, I kept that cake flour substitution in mind when I came up with this rhubarb muffin recipe: instead of using 250 grams (2 cups) of all-purpose flour, like I did in the honey blueberry muffins recipe, I used slightly less all-purpose flour and replaced it with ground almond. This substitution produces slightly denser, more moist muffins that are quite impressive.

The ingredients

This recipe is based on my best fruit muffin recipes, and the ingredients are as follows

• flour mixed with ground almond to reduce the gluten protein in the recipe making a slightly denser, but also more tender muffin
• large eggs
• sugar—sometimes I use a little less, and other times, I may substitute a portion of sugar for a liquid sugar, like honey
• butter—I prefer baking with butter, but if you must make a baking substitution here, use 80 mL (⅓ cup) of canola oil, for example. You could use up to 125 mL (½ cup) oil, but this might lead to a more delicate muffin. It all depends what you are going for!
• sour cream—you could use buttermilk, but sour cream adds so much flavour and richness to the muffin batter. I'm obsessed!
• both baking powder and baking soda are the chemical leaveners I add to this muffin recipe. You need the baking soda in this recipe because these muffins have sour cream, an acidic ingredient in the recipe. The baking soda helps neutralize the acid so that the baking powder can do its job
• rhubarb: in this case, we are working with chopped rhubarb, fresh or frozen, but you can use a mix of strawberries and rhubarb to make these strawberry rhubarb muffins with streusel topping. Remember too much fruit can lead to muffins that are wet, hard to eat, that may collapse when they cool, and that lack structure and fall apart.

Tip: read about baking soda versus baking powder if you aren't sure what the difference is between them!

This recipe for rhubarb muffins with streusel topping is almost identical to the honey blueberry muffins I mentioned earlier, but with a few key differences:

1. I reduced the all-purpose flour by 60 grams (½ cup) in the batter and replaced it with the same portion of ground almonds, adding 50 grams (½ cup)
2. I used sour cream instead of buttermilk. Both are acidic ingredients commonly used in baking, but remember that cultured buttermilk has virtually no fat, while sour cream has 14 %, so sour cream leads to a rich, more tender muffin. I added 125 mL (½ cup) of sour cream, but you can use 80 mL (⅓ cup) of buttermilk if you prefer
3. I used slightly more fruit, by weight, because I wanted to make sure there was enough rhubarb in almost every bite, without adding so much that the batter becomes wet. If you want to make strawberry rhubarb muffins, replace half the weight of rhubarb with strawberries, and you can follow this recipe for strawberry rhubarb muffins with streusel topping

Useful tools for making muffins

Sure, muffins are easy to make and I like to mix them by hand, so no special electric mixers are required! Still, there are a few tools that will make your muffin-baking sessions a little easier:

1. Muffin pans: for regular muffins, you can't get away without a muffin pan. And if you can, please invest in two 6-cup muffin pans (like this Wilton pan on Amazon) or one bigger 12-cup muffin pan (like these Wilton pans on Amazon). This way you will be ready to make full batches of most recipes, which can yield anywhere from 8 to 12 muffins, depending on how much batter you scoop per cup. 
2. Paper liners, parchment liners, silicone liners: we can debate over which is better for muffins, but personally, I like disposable paper liners (like these on Amazon that you would use for cupcakes too). For lower-fat muffins or muffins with less sugar, these can stick to paper liners. In this case, use parchment liners (Amazon) or silicone liners (Amazon). Savoury muffins, for example, work best baked in either of these.
3. Large cookie scoops: Some call them "dishers" and they are the most reliable scoops I've found on Amazon. They can handle firm doughs without breaking because the release mechanism is separate from the handle! This gives you a better, firm grip on the handle, without the risk of damaging the lever. The handles are different colours according to the size. 
4. Cake tester and/or instant-read thermometer: if you bake a lot, you can probably gently poke muffins with your fingertip and instinctively know when they are done baking. The rest of us have to use a cake tester or thermometer to check if muffins are done baking.

Baking big muffins

Lately, when I've been making muffins, I've been baking "bigger" muffins, so scooping more batter per muffin cup. So while you could easily make 10 or even 12 regular or small-sized muffins with the recipe below, this time, I opted to divide the batter between 8 muffin cups to yield big, bakery style muffins with impressive muffin tops. 

When baking bigger muffins, I wondered if the muffins would bake more evenly if you leave a few empty muffin cups in the tray. So I tested baking 8 big muffins in two pans that could accommodate 6 muffins each: I only filled 4 muffin cups out of 6 in each pan to bake the 8 muffins.

While I assumed this would allow for more air circulation and for the pan to heat up more evenly underneath and faster, without having the batter slow it down. I noticed no difference whether I filled a 6 cup pan with the batter for 6 muffins or 4.

Some may fill empty muffin cups with water, but I don't think this is necessary either. The water would slow the heating of the muffin cups and perhaps even out the heat, but again, I haven't noticed anything different from doing this extra step. That being said, if you have a preferred method for evenly baking muffins, I'm all ears! Let me know in the comments!

These big rhubarb muffins with sour cream and streusel are perfect, if you ask me: super moist, super flavourful, with a lovely texture that isn't too heavy, nor too light. This recipe yields hefty bakery-style muffins, but feel free to divide the batter to make more "smaller" muffins and just reduce the baking time accordingly. A smaller rhubarb muffin would take about 20 minutes to bake through at such a high temperature, so you'll need to keep an eye on them.

Remember, regardless of the size of the muffins you are baking, make sure to check that they are done baking before taking the pan out of the oven. Nobody likes a gummy, under-baked muffin.