What's the difference between Old Fashioned Oats and Quick Oats?

Old fashion oats cooks up faster. I would use the quick oats since that's what the recipe called for.

Yes, the texture will be a bit chewier, and you might need to adjust your liquid amount and add a little extra. But don't use steel cut oats instead of quick oats, they are barely processed and take forever to cook. They're delicious, but I wouldn't try to interchange them in a recipe unless I could add a lot of cooking time without ruining the end product.

Old fashioned oats are less processed than the quick cooking oats. If you have a food processor or a blinder you can make quick cooking oat by runnung them through the processor or blender, but be careful not to run them too long or you will have flour.

I am not sure of the difference, except quick oats have been partly precooked. You probably could use old fashioned oats, provided you cooked it for a lot longer. Here is a recipe using old fashioned oats: WINERY'S OATMEAL COCONUT MUFFINS 1 c. rolled slow cook oats 1 c. buttermilk 1 c. sifted flour 1/2 tsp. salt 1/2 tsp. baking soda 1 1/2 tsp. baking powder 1/2 c. melted shortening (do not use butter) 1/2 c. brown sugar 1 egg 3/4 c. shredded coconut Strawberry preserves Preheat oven to 400 degrees. Soak oats in buttermilk for at least 30 minutes. Sift flour with salt, baking soda and baking powder. Blend together melted shortening, brown sugar, coconut and egg. Then blend in thoroughly oatmeal and buttermilk mixture. Stir in dry ingredients, mixing only enough to moisten. Spoon into greased muffin tins. Using small teaspoon, place 1 teaspoon strawberry preserves in each muffin. Cover with a dab of dough. Bake at 400 degrees for 20 minutes. Makes 1 dozen.