What's for dinner tonight? Beef Tenderloin Crostini

Beef Tenderloin Crostini This recipe is from a fellow foodie Sherri Logan Williams , Thanks Sherri!!
Ingredients
1/2 lb rare beef tenderloin, thinly sliced (Pre roast to 135 degrees then let rest to 140 degrees.)
1 12 inch french bread baguette
2 Tbsp blue cheese crumbles
1 tsp prepared horseradish
1 tsp granulated garlic
1 tsp dry italian seasoning
8 oz sour cream
2 Tbsp mayonnaise
1/2 c extra virgin olive oil
1 pkg spring mix salad
1 lg onion, thinly sliced
1/2 stk butter
1 Tbsp brown sugar
salt and pepper, to taste
Combine blue cheese, horseradish, sour cream, mayo, granulated garlic, salt and pepper. Chill for at least 30 minutes. Add the butter to frying pan. Add onions and brown sugar. Cook onions on low-medium heat until caramelized this should take about 10-15 minutes Slice french bread baguette in 1/4 inch slices, brush with the olive oil and sprinkle with Italian seasoning. Broil in oven until golden brown. On a large platter, arrange the crostini slices. Spread the blue cheese sauce on the crostini, add some spring mix salad leaves, layer the beef and top off with the caramelized onions.