In a medium sized bowl, mix together the yeast, sugar, and 1/2 cup of the warm water. Allow the mixture to rest, stirring every couple minutes, for 5-10 minutes until the yeast has dissolved and there are a few small bubbles along the edge of the bowl. Stir in the remaining warm water and set aside.

In a large bowl, mix together the flour and the cream of tartar. Then add the yeast mixture and stir quickly until well blended, about 2-3 minutes. Cover the bowl with plastic wrap and set in a warm place for one hour to rise. If it's chilly and you don't have a sun-facing window, like myself, then you can set the bowl on top of a heating pad (the kind you use for muscle cramps) turned on to low. After the hour's passed, add the salt and beat the batter with an electric mixture for one minute. Then cover the bowl and place it in a warm place for another 20 minutes.

Mix together the baking soda and the warm milk and then stir it into the batter until completely combined. Heat a large griddle and use a ladle to pour some of the batter onto the griddle, pouring just enough to create a saucer-sized disk. Holes should begin appearing in the top of the crumpet as it cooks. If they don't, add a few more tablespoons of warm water to the batter. Once the crumpet has holes and the bottom is golden brown, about 5 minutes into cooking, flip it over and cook the side with holes for a few minutes until gold in color.

Remove the crumpet from the griddle and set on a rack to cool, (if you put it directly onto a plate it will get a bit soggy on the bottom from the heat evaporating), until you're finished making all the crumpets. Serve with butter and jam.