In a medium bowl, combine all ingredients and whisk together until smooth and well combined. Let mixture sit in refrigerator for 1-2 hours or overmight. Store leftovers in refrigerator in an airtight container for up to 2 weeks.
In a large heavy saucepan, add enough canola oil to fill just over a third full. Clip a frying thermometer onto the pan and heat the oil over medium heat until oil reaches 375 degrees.
While the oil is heating, in a medium bowl, whisk together the flour, baking powder and baking soda. Add the club soda and the olive oil.
Dip the aspargus stalks into the batter, one or two at a time, then add to the hot oil and fry 3 or 4 stalks at a time for about 70 seconds, until golden brown, turing with tongs to promote even browning. Remove from oil and place on a wire rack placed over a baking sheet.
Serve on platter with horseradish cream sauce.