1 For the Mushrooms:
2 - Heat oil in a frying pan over a medium high heat
3 - Add Mushrooms, cook until golden and there is little moisture remaining
4 - Remove mushrooms, set aside
5 - Reduce heat to medium
6 - In the same pan, melt butter
7 - Add shallot and garlic until tender, 1-2 minutes
8 - Add the cooked mushrooms
9 - Season with salt and pepper
10 - Set aside and keep warm
11 - Slice the sourdough and toast
12 To make the Bearnaise:
13 - Pour a few centimetres of water into a saucepan and bring to a low simmer
14 - Select a heat proof mixing bowl that will comfortably sit atop the saucepan, well above the water to create a double boiler
15 - Place the egg yolks and vinegar in the heatproof bowl and beat the eggs with a whisk until fluffy
16 - In another saucepan, melt the butter carefully, then add your chopped tarragon
17 - In a steady stream, slowly add the melted butter to your egg mixture, continually whisking
18 - Once incorporated into the thickness you desire, remove the bowl from the pan and season with lemon juice, salt and white pepper to perfection
19 - Keep Bearnaise warm on the residual steam from the saucepan, removed from the heat
20 To poach the eggs:
21 - Fill a small saucepan with 3 inches of water and bring to boil. Add a splash of vinegar and with a whisk, furiously spin the water to create a whirlpool
22 - Immediately drop the egg into the centre of the vortex and cook until the whites are set and the yolks are still soft, about 2-4 minutes
23 - Remove with a slotted spoon
24 To Assemble:
25 - Spread a little of the Bearnaise over the toast
26 - Top with mushrooms, the poached egg and a spoonful of warm Bearnaise
27 - Serve immediately