Tiramisu French Toast

In a bowl, whisk the egg yolks and granulated sugar together until the mixture lightens in color and becomes slightly thick.
In a saucepan over medium heat, warm the milk, heavy cream, vanilla bean paste, instant espresso, and salt until steaming but not boiling.
Slowly stream the warm milk mixture into the yolk mixture while whisking constantly.
Return everything to the saucepan and cook over medium-low heat, whisking constantly, until the anglaise thickens slightly and coats the back of a spoon.
Remove from heat and use warm or at room temperature.

Place the white chocolate in a heatproof bowl and pour the hot heavy cream over it. Let sit briefly, then stir until smooth.
Once slightly cooled, add the mascarpone and mix until fully combined.
In a separate bowl, whip the heavy cream with the vanilla extract and powdered sugar until soft peaks form.
Gently fold the whipped cream into the mascarpone mixture until light, smooth, and fluffy. Chill until ready to use.

In a shallow bowl, whisk together the half-and-half, eggs, sugar, and vanilla extract.
Dip each slice of brioche into the mixture, letting it soak briefly on each side without oversaturating.
Heat a skillet over medium heat and melt about 1 tablespoon butter.
Cook the French toast for 2½ to 3 minutes per side, until deeply golden and cooked through.
Transfer cooked slices to a wire rack to keep them crisp while you finish the remaining batches, adding more butter as needed.

Place the warm French toast on a plate.
Pipe the whipped mascarpone on top, or add a generous dollop with a spoon and gently spread.
Pour the coffee anglaise around the French toast on the plate.
Lightly dust the mascarpone with cocoa powder.
Serve immediately.