Heat 1 tbsp oil in large saucepan over medium-high heat.
Add beef and break it up into smaller crumbles. Cook a few more minutes and add in your mushrooms. Continue to cook until you get a good brown on the beef. Brown = flavour.
In a bowl or cup mix together 1/2 cup water, fish sauce, sugar, sesame oil, soya sauce and stir. Pour into beef mixture, cook until almost all liquid is gone and flavours combined. Set aside to cool a bit.
To make the salsa, in a bowl mix together mango, red onion, jalapeno, cilantro, pinch of salt and lime juice. Set aside.
To make toast cups, preheat your oven to 350F
Cut the crusts off each piece of bread. Cut each piece into four equal squares.
Spray mini muffin tins with cooking spray or brush with melted butter.
Flatten each piece of bread a little with your hand or a rolling pin. Gently press each bread square into a mini muffin cup. Give another quick spray or brush of melted butter. Continue until you have filled all 12 mini muffin cups or if you have two pans, 24. If you do not have two pans, you will need to do this two times.
Place in oven and bake for 6-8 minutes or until the bread has turned lightly brown. Remove from pan, place on platter and begin assembling.
Scoop a little beef mixture into each toast cup. Top with a small amount of the mango salsa. If you have juice in the salsa sprinkle a little on top. You can either top with a cilantro leaf or serve as is. Serve immediately.