What is 1/4 of 1&1/2cups

ehhhh... great for banana bread, but when i've used 100% oat flour in my chocolate chip cookie recipe, the cookies are very crumbly. i don't think the binding properties of oat vs. wheat are similar. i've read to use the ratio for every 1 cup of oat flour add 2 1/4 teaspoons baking powder. continue to use baking soda as recipe requires. but i use a whole bag of mini chocolate chips in my recipe, so the chocolate definitely helps the oat flour to bind ~! happy baking.

I added about a cup more liquid (milk & tad bit of oil). They baked up perfectly and taste great. The texture is perfect. Lesson learned.
Thanks for your comments.

AP flour is 60% bread flour, 40% cake flour. You're not going to get the same structure.

I've never used oat flour, except ground up oatmeal in cookie dough. Makes cookies chewy. I'm guessing oat flour will absorb a lot of liquid, hence you dry muffin batter. Good call on adding more liquid!

Oat flour absorbs liquid more readily than most flours in my experience, so it was probably the flour switch that made it dry. I usually combat this by adding (like you did) more liquid--try things like orange juice or soymilk for different flavors. If you're just trying to make your muffins more hearty, substituting oat flour in a smaller quantity should also work. I have a general rule to keep it to about 1/2 cup substituted flour for a 12-muffin recipe.

Oat flour has a much lower gluten content than regular all-purpose flour, so you can't substitute oat flour completely for APF without making some sort of adjustment. Your recipe won't hold together. (In fact, oats are naturally gluten-free; it's the processing methods that add a gluten content to some oat products.)

I just made muffins from a recipe I've never used before. It called for 2 3/4 Cup APF and I substituted 3/4 of that with oat flour. The batter ended up VERY dry. I added more liquid until it was the consistency of muffin batter. They seam to have turned out fine.
I just wonder if it was the flour exchange that made it dry or if someone wrote the recipe wrong. Or maybe it was suppose to be that dry??

What are you making? Quick breads and muffins are generally more forgiving than cakes, cookies and biscuits, so I'd try it on those first. If you're using oat flour to make something gluten-free, there are great resources on the web. Check out the blog elana's pantry. http://www.elanaspantry.com/