Steak
Preheat the oven to 400°F.
Season both the rolled caps of ribeye with salt and pepper.
Rub all sides of the steaks with oil and heat a medium cast-iron skillet over medium high heat. Add the steaks to the hot skillet, and cook, turning once, for 4 minutes, or until the steaks are browned well on both sides. Transfer the skillet to the oven and cook the steaks to desired doneness, (internal temperature has reached 110°F (43°C) for rare or 130°F (54°C) for medium) about 5 to 8 minutes. Transfer steaks to a cutting board and let rest for 10 minutes.
Meanwhile prepare crostini.
Crostini
Brush both sides of the baguette slices with oil and place on a rack inside a large rimmed baking sheet. (Note: Cutting the baguette on the diagonal makes for a larger crostini. If you would like a smaller version, simply slice the baguette crosswise. This will result in nearly twice the number of appetizers.)
Place the baking sheet in the oven and let bake until lightly browned, about 8 to 10 minutes. Remove and let cool on the rack.
Horseradish Aioli
For Horseradish Aioli: In a small bowl, combine all the ingredients.
Gorgonzola Garlic Butter
For Gorgonzola Garlic Butter: In a small bowl, combine all ingredients.
Assemble the Crostini
Slice the steaks thinly crosswise, then cut into strips and chop into small pieces.
Spread half of the crostini with the Horseradish Aioli and the other half with the Gorgonzola Garlic Butter. Top each with some of the steak. Sprinkle a little flakey sea salt on to the steak.
Garnish the horseradish crostini with an additional grating of fresh horseradish and a sprinkling of chives.
Garnish the Gorgonzola crostini with additional crumbled Gorgonzola. Serve at room temperature or slightly warmed.
