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Ketchup and Mustard Burger

Ketchup and Mustard Burger

Recipe by Chef Rachel Paghunasan, University of Southern California

YIELD: 1 burger (plus more of ketchup mixture)

For fennel ketchup:
1 lb. fennel bulb, large dice
2 lbs. roma tomatoes, whole
½ lb. red onion, peeled, large dice
1 oz. garlic cloves
½ cup olive oil/canola blend
¼ cup brown sugar
1 oz. apple cider vinegar
2 oz. tomato paste
kosher salt, to taste
ground black pepper, to taste

For roasted king mushrooms:
4 lbs. king trumpet mushrooms, sliced 1/3” thick lengthwise
2 oz. olive oil/canola blend

For burger:
6 oz. grassfed ground beef/mushroom mix: 80/20
kosher salt, to taste
ground black pepper, to taste

To assemble:
½ oz. Frilly mustard
½ tsp. olive oil
kosher salt, to taste
ground black pepper, to taste
1 onion bun, sliced and toasted
2 oz. fennel ketchup
1 patty
3.4 oz. king trumpet mushrooms

1.    For fennel ketchup: in mixing bowl, thoroughly coat fennel, tomatoes, onion and garlic with olive oil, salt and black pepper. Place fennel mixture onto sheet pan and roast in 400°F oven for 10 minutes or until vegetables are caramelized.
2.    Meanwhile, in medium saucepan on low heat melt brown sugar until caramel forms. When brown sugar has melted, add roasted vegetables into saucepan. Mix vegetables and caramel together, taking care not to burn. When thoroughly combined, remove from heat.
3.    Using immersion blender, blend sugar and vegetable mixture until smooth. Add apple cider vinegar, tomato paste, salt and pepper.
4.    When mixture is smooth strain into storage container. Allow to cool and set aside.
5.    For mushrooms: Toss mushrooms with oil. Place on 375°F flat top. Allow mushrooms to caramelize on both sides. Hold hot and set aside.
6.    For burger: In mixing bowl, blend mushroom/ground beef mix, salt and pepper. From into 6 oz. patty. On grill, cook patty to desired doneness.
7.    To assemble: In mixing bowl, toss together mustard, olive oil, salt and pepper. Set aside.
8.    Place warm bun on prep area and spread with 1 ½ Tbsps. fennel ketchup on both sides of bun. Place mustard on bun. Place patty, then mushrooms and cover with bun top. Serve hot.

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