This zesty and flavorful party appetizer can be served warm or room temperature with crackers for any brunch or gathering.
Preheat oven to 325ºF. Position rack in centre of oven.
In a food processor fitted with metal blade, process crumbs and yellow mustard seed for 10 seconds. Place into a bowl with butter. Mix together until it resembles wet sand. Press into bottom of cheesecake pan. Place into preheated oven for 10 minutes. Remove and let cool on a wire rack.
Meanwhile in a medium skillet, heat canola oil over medium heat, then add leeks and sauté until opaque, about 5 minutes. Remove from heat and let cool in pan.
In a food processor fitted with metal blade, process cream cheese, eggs, flour, sugar, yellow mustard seed, garlic powder and thyme for 2 minutes, until smooth. Scrape sides of the bowl and process additional 1 minute. Place into a medium mixing bowl.
With a rubber spatula, swirl Dijon mustard into mixture, being careful not to blend it too much as you want to see swirls of mustard.
Pour into prepared pan on top of crumb base, smooth to the sides. Bake 40 to 45 minutes or until top is light brown and dry looking. Cool on wire rack for 60 minutes prior to unmolding. Cut into 12 slices before serving.
Serve with crackers.
You can replace the leeks with: 1/2 cup onions, chopped and caramelized or 1/4 cup shallots, chopped.