Some people call them Popovers but we've always called them Yorkshires. They are delicious dipped in gravy so I always make them when I'm making a beef roast. I usually make 24 mini Yorkshires because 12 is never enough. :) These are great the next day stuffed with leftover roast so you may want to make lots!
I cook in a convection oven, but a regular oven would work just fine, you might just have to keep it a bit hotter for a bit longer. If your Yorkshires aren't rising or look like they are starting to fall, turn the oven back up 25-50 degrees and they will still be okay. Don't be scared to adjust your oven temperature, your oven may be totally different than mine.

Step 1: Ingredients

24 Mini Yorkshires

3 cups flour
3 cups milk (I use skim but you'll get higher ones if you use whole or even 2%)
The flour always matches the milk for measuring.
About one tablespoon of salt
5-6 eggs (I use extra large from my chicken coop)
About 3 good tablespoons of oil
Oil for cups (divided)

Step 2: Blender or a Bamix

Use a Blender or a Bamix. Do not use beaters. I've tried beaters and you just can't get the air into the mix and end up with Yorkshires that don't rise very high.

Step 3: Combine Ingredients

Combine eggs, milk, flour, salt, and oil into blender. Use the highest setting you have because you want to get lots of air into the mix and really beat those eggs. After the first whirl scrape sides of blender and whirl again. All those air bubbles are a good thing. You'll whirl a few more times, and then a final time just before filling the cups. If your blender isn't big enough you can half the recipe or reduce flour, milk, or an egg.

Step 4: Oven Temp

Set your oven at 450 degrees F.

Step 5: Yorkshire or Muffin Tins

Grab that Yorkshire pan or if you don't have one use a plain muffin tin. Add about 1/4-1/2 teaspoon of oil into each cup (do NOT use olive oil). Pop your pan in the oven and get the oil smoking hot. (You might want to hit the snooze button on your kitchen smoke alarm.)

Step 6: Filling the Cups

When oil is smoking, fill each cup almost full. Everything will be very hot!

Step 7: Cooking

After about 12 minutes here's what mine looked like. You will get even higher results if using 2% or whole milk. I've had them rise right out of the pan and continue to cook while laying sideways on my oven racks!

Step 8: Reduce Heat

Turn your oven down to 400 for 10 minutes. (If you are using a regular oven instead of a convection you can turn your oven down again to 350 for another 5 or 10 minutes) Once they are done I pull them out of the pan and lay them sideways to cool.

Tip: If you plan on transporting your Yorkshires I find it best to overcook them a tad so they don't get squished in the box. I've made over 100 and they did fine until they got to our local Legion for dinner.