EmailFinisher.php

<?php
namespace WM\StarterKit\Finishers;

/**
 * @author Benjamin Klix | die wegmeister gmbh
 */
class EmailFinisher extends \TYPO3\Form\Finishers\EmailFinisher {

    /**
     * Extends the functionality of the default parseOption() method
     * by making node-properties available
     *
     * @param string $optionName
     * @return mixed|string
     */
    protected function parseOption($optionName) {
      if (!isset($this->options[$optionName]) || $this->options[$optionName] === '') {
        if (isset($this->defaultOptions[$optionName])) {
          $option = $this->defaultOptions[$optionName];
        } else {
          return NULL;
        }
      } else {
        $option = $this->options[$optionName];
      }
      if (!is_string($option)) {
        return $option;
      }

      if(preg_match('/{node\.([^}]+)}/', $option, $matches)) {
        $renderingOptions = $this->finisherContext->getFormRuntime()->getRenderingOptions();

        if(isset($renderingOptions['node'])) {
          $node = $renderingOptions['node'];
          if($node->hasProperty($matches[1])) {
            $property = $node->getProperty($matches[1]);

            if(!empty($property)) {
              return $property;
            }
          }
        }
      }

      return parent::parseOption($optionName);
    }
}

Form.html

{namespace form=TYPO3\Form\ViewHelpers}
<div{attributes -> f:format.raw()}>
<f:if condition="{formIdentifier}">
    <f:then>
        <form:render persistenceIdentifier="{formIdentifier}" presetName="{presetName}" overrideConfiguration="{renderingOptions:{node: node}}" />
    </f:then>
    <f:else>
        <p>Please select a valid Form identifier in the inspector</p>
    </f:else>
</f:if>
</div>

Form.yaml

type: 'TYPO3.Form:Form'
identifier: ContactForm
label: Kontakt
renderables:
  -
    type: 'TYPO3.Form:Page'
    identifier: page-one
    renderables:
      -
        type: 'TYPO3.Form:SingleLineText'
        identifier: Name
        label: Name
        validators:
          - identifier: 'TYPO3.Flow:NotEmpty'
        properties:
          elementClassAttribute: 'form-control'
          wrapperClassAttribute: 'form-group'
        defaultValue: ''
      -
        type: 'TYPO3.Form:SingleLineText'
        identifier: Email
        label: EMail
        validators:
          - identifier: 'TYPO3.Flow:NotEmpty'
          - identifier: 'TYPO3.Flow:EmailAddress'
        properties:
          elementClassAttribute: 'form-control'
          wrapperClassAttribute: 'form-group'
        defaultValue: ''
      -
        type: 'TYPO3.Form:MultiLineText'
        identifier: Message
        label: Message
        validators:
          - identifier: 'TYPO3.Flow:NotEmpty'
        properties:
          elementClassAttribute: 'form-control'
          wrapperClassAttribute: 'form-group'
          rows: 1
        defaultValue: ''
finishers:
  -
    identifier: 'WM.StarterKit:Email'
    options:
      templatePathAndFilename: resource://WM.StarterKit/Private/Templates/Email/Contact.html
      subject: '{node.subject}'
      senderName: '{node.senderName}'
      senderAddress: noreply@homepage.de
      recipientName: '{node.recipientName}'
      recipientAddress: '{node.recipientAddress}'
      replyToAddress: '{Email}'
      format: html

NodeTypes.yaml

'WM.StarterKit:ContactForm':
  superTypes:
    - 'TYPO3.Neos.NodeTypes:Form'
  ui:
    label: 'Contact Form'
    group: general
    icon: icon-envelope-alt
    inspector:
      tabs:
        mail:
          label: 'Contact form settings'
          position: 11
          icon: icon-envelope-alt
      groups:
        mail:
          label: 'Contact form settings'
          position: 10
          tab: mail
  properties:
    subject:
      type: string
      defaultValue: ''
      ui:
        label: 'Subject'
        inspector:
          group: mail
      validation:
        'TYPO3.Neos/Validation/NotEmptyValidator': []
    senderName:
      type: string
      defaultValue: ''
      ui:
        label: 'Sender name'
        inspector:
          group: mail
    recipientName:
      type: string
      defaultValue: ''
      ui:
        label: 'Recipient name'
        inspector:
          group: mail
      validation:
        'TYPO3.Neos/Validation/NotEmptyValidator': []
    recipientAddress:
      type: string
      defaultValue: ''
      ui:
        label: 'Recipient address'
        inspector:
          group: mail
      validation:
        'TYPO3.Neos/Validation/NotEmptyValidator': []
        'TYPO3.Neos/Validation/EmailAddressValidator': []

Settings.yaml

TYPO3:
  Form:
    presets:
      default:
        finisherPresets:
          'WM.StarterKit:Email':
            implementationClassName: 'WM\StarterKit\Finishers\EmailFinisher'
            options: {}